The development of the BMP-1 was linked to the development of the tanks in the Soviet Army. In the mid-50's, requirements for a prospective new medium tank were drawn up, and in doing so, it was realized that existing armoured personnel carriers would be left behind during fast-paced offensive maneuvers if the new machine was realized. Moreover, the motorized infantry would not be able to fight effectively in an environment contaminated by weapons of mass destruction. Closer cooperation between tanks and infantry was identified as a mandatory requirement under the new vision of mechanized warfare for the survival of both the tank forces and the infantry, so it was decided that an entirely new class of troop carrier was required for the future Soviet Army.
From 1959 to 1960, the GBTU (Main Armored Directorate) carried out research work on the development of the concept and the development of basic tactical and technical requirements for the new combat vehicle. During the developmental process, all existing domestic and foreign troop carriers were analyzed with the intent to identify promising solutions, and the objective was to create a Soviet IFV that was superior to the best foreign counterpart that was projected to appear in the late 1960's based on current trends.
It was to be a fully armored and sealed amphibious vehicle with high off-road mobility that could accommodate 7-10 men. The vehicle had to be fast enough to keep up with tanks and it needed to have the same travelling range as tanks at the very minimum. Full NBC protection was mandatory, and the passengers had to be able to use their personal weapons from within the vehicle without compromising the hermetic seal of the vehicle. When the passengers had to dismount, it was stipulated that they must be able to do so conveniently and with concealment and protection from incoming fire. In addition to the small arms carried by the passengers, the prospective IFV was required to have a powerful rapid-fire weapon with anti-tank capabilities to ensure its ability support infantry during offensive operations and repel the armoured vehicles of the enemy during defensive operations. However, a fire-on-the-move capability was not required.
Due to the large number of motorized rifle units in the Soviet Army and their high concentration relative to tank units, it was determined that the prospective IFV had to be inexpensive and simple to produce. The size and weight of the IFV had to be as low as possible to minimize metal consumption, it had to have a simple construction for ease of manufacture, and it had to use existing and inexpensive components from the automotive tractor industry.
Initially, an autocannon with a caliber of 20mm or 23mm was specified as the main armament of the prospective IFV, but this specification was reevaluated in the early 1960's. Instead, the feasibility of autocannons in the 30mm, 37mm and 45mm calibers and medium caliber semi-automatic guns in the 57mm, 76.2mm and 73 mm calibers with rocket-assisted projectiles was investigated. The caliber of the weapon was constrained by its recoil force which had to be within certain limits because an excessively large turret ring would take up too much space and thus reduce the number of passengers or force the size of the vehicle to be increased. As a result of a general directive by Soviet Premier Nikita Khrushchev to reorient the direction of Soviet military weapons technology development from traditional ballistic weapons towards rockets and rocket-assisted weapons, the GBTU chose the 73mm smoothbore gun concept with rocket-assisted grenades. In theory, the decision to install this weapon drastically widened the scope of the prospective IFV, as it provided the capability to destroy any enemy armoured vehicle and also eliminate entrenched enemy targets and machine gun positions in support of dismounted infantry who would be responsible for neutralizing enemy infantry with their own small arms.
After this decision was made, the Tula KBP Design Bureau (now the KBP Joint Stock Company) designed the 73mm 2A28 cannon and created a prototype one-man turret that featured an autoloader with a capacity of forty rounds and an integrated launch system for the "Malyutka" ATGM, of which four would be carried. The main gun was supplemented by a PKT coaxial machine gun. There was no requirement for a stabilizer, so the prospective IFV could only fire accurately when it was stationary. The turret ring diameter of this turret was 1,380mm, which was considered acceptable. All prospective IFV designs were required to fulfill the criteria put forth by the GBTU and all had to be compatible with the new one-man turret.
The participants of the competition were the design bureaus from Chelyabinsk (ChTZ), Kurgan (KMZ), Altai (ATZ) and Volgograd (ZiL). The Object 765 first prototype was made at ChTZ in 1962, the second in March 1963. In 1963 the vehicle passed factory tests and it was deemed suitable for conducting military tests. In July 1961, the project documentation from the ChTZ, ATZ, KMZ and ZiL design bureaus was evaluated. A total of eleven designs were submitted, of which five met the general requirements and proceeded to military tests at proving grounds in Rzhevka and Kubinka. They were the Object 19, Object 765, Object 911, Object 914, and Object 1200. Most of these prototypical designs incorporated a water jet, and many of them used an identical system to that of the PT-76. Of the five competing prototypes, the Object 765 and Object 914 were the only fully-tracked designs. The Object 1200 had a wheeled chassis in an 8x8 configuration, while the Object 19 and Object 911 both featured a combination of wheels and tracks. The Object 19 had four wheels in a 4x4 configuration that was supplemented by a pair of short retractable tracks between the wheels on each side, whereas the Object 911 had a pair of tracks that occupied the entire length of the hull and were supplemented by four retractable wheels.
During the course of testing, the Object 911 and Object 19 were eliminated rather quickly as they were found to be extremely complex but lacked any tangible advantage over a fully tracked or wheeled vehicle. The Object 1200 was a very modern design and it was an extremely capable combat vehicle, but it had insufficient off-road mobility compared to tanks due to its wheeled propulsion system. The Object 914 was a fully tracked vehicle and possessed very good tactical-technical characteristics, but its passengers were forced to egress through roof hatches due to its use of a rear engine and transmission. The Object 765 had a number of minor flaws, but it was the only design to fulfill virtually all of the requirements put forth by the GBTU. The layout of the various competing models is shown below.
In 1965, the Object 765 design was proclaimed as the winner of the competition. Aside from the primary features of the Object 765 that defined it as the world's first true IFV, there were also a number of details that marked its uniqueness among other tracked troop carriers. For instance, it was not steered with tillers like the MT-LB and the BTR-50, but instead had a T-bar steering system with excellent hydraulic assistance. This marked the progressiveness of the BMP among its foreign counterparts as well, as APCs like the British FV432, American M113, French AMX-10P and German Spz. 12-3 were all steered with tillers.
Sergey Suvorov writes in his book "Боевые машины пехоты БМП-1, БМП-2 и БМП-3. «Братская могила пехоты» или супероружие" (BMP-1, BMP-2 and BMP-3 infantry fighting vehicles. "Mass grave of infantry" or a superweapon) that when it came time for the Object 765 to enter service in the Soviet Army as the BMP, the long term viability of the vehicle came into question due to its high cost and somewhat complex construction. Broadly speaking, a high price tag was part and parcel of the creation of a radically new combat vehicle, but it was considered particularly high in comparison with existing armoured personnel carriers. Although the Object 765 was a lightweight vehicle, it was not as simple to produce as older tracked APCs like the BTR-50P, and its design did not make use of existing components in significant quantities. There was also some debate as to whether or not it offered enough advantages over the much cheaper BTR-60 to warrant its increase in unit price. According to Suvorov, it was determined that in a conventional large scale war, a cheaper wheeled APC like the BTR-60PB was much more cost efficient. A large scale nuclear war - where a vehicle like the BMP would excel - was seen as an increasingly unlikely scenario, mainly due to the fact that the USSR had managed to field submarine-launched ballistic missiles (SLBM) in the early 1960's and had therefore improved their nuclear deterrence capability to such an extent that a mutually assured destruction (MAD) situation was created between the USSR and the USA.
However, the relatively high price of the BMP was eventually accepted after some motorized infantry tactics were thoroughly reworked to make full use of the capabilities of the new vehicle. The BMP officially entered service in 1966 with mass production beginning in the same year at Kurganmashzavod (Kurgan tractor plant).
It was decided that only the motorized rifle units in close proximity to NATO forces in Europe would be equipped with the new BMP. The motorized rifle regiments integrated into tank divisions were also equipped with BMPs to maximize their shock action capability. Second line and reserve units would remain equipped with cheaper wheeled BTRs like the BTR-60PB which also entered service in 1966. In the end, the BMP turned out to be the most mass produced IFV in human history with around 40,000 samples - including a number of specialized variants - produced by the time production ended in the USSR in 1983. It was formally replaced by the BMP-2 in 1980.
In this article, we will only be examining the five primary variants of the generic BMP-1 IFV. The first iteration of the BMP design is the Object 765 Sp.1 from 1966, also known simply as "BMP", without the "-1" suffix. It is characterized by the stubby bow of its hull. The second variant is the Object 765 Sp.2 from 1969. It is distinguished from the BMP by the more elongated bow, and it is the first model to be officially designated as the BMP-1. The third variant is the Object 765 Sp.3 from 1973. This modification introduced a new mode for its autoloader for compatibility with HE-Frag rounds, with manual loading by the gunner. The fourth and final variant is the Object 765 Sp.4 from 1979, better known as the BMP-1P. It is essentially the same as the Object 765 Sp.3 except for the missile system. The BMP-1P has an external 9P135 missile launcher and had all of the control equipment for "Malyutka" missile system removed. The BMP-1P replaced the BMP-1 on KMZ production lines beginning in 1979, and in the same year, all BMP-1s coming into depots for capital overhauls began to be modernized to the BMP-1P standard.
COMMANDER'S STATION
In a BMP, the commander of the vehicle was also a motorized rifle unit commander. Depending on the specific vehicle in a standard motor rifle company, the vehicle commander may be the commander of the company, of a platoon, be the deputy to the platoon commander, or be the commander of a squad. In a standard platoon, the commander typically dismounts together with the passengers when required and acts as the squad leader, while the platoon commander remains in his vehicle.
When fighting from inside the vehicle, the commander of a BMP acts as a typical vehicle commander. He issues orders to the rest of the crew and to the passengers, who open fire from their firing ports or dismount from the vehicle only when instructed by the commander. To facilitate his duties, the commander is given a rotating cupola which includes a forward-opening hatch and three periscopes. His primary vision device was the TKN-3B, used not only for general surveillance but also fire correction, when working together with the gunner. The TKN-3B is distinguished from the TKN-3 by the lack of a target cueing system owing to the location of the commander's station. The TKN-3B uses a 2-stage cascading tube light intensifier with 0-generation photocathodes. It has no useful passive viewing capability, depending entirely on illumination from the OU-3GA2 infrared spotlight.
The hatch is of a semicircular shape and it is locked with a simple latch. Also, the hatch features a safety mechanism linked to the powered traverse system of the turret that locks the turret in place once the latch is unlocked. The system senses this via a spring-loaded solenoid button maintains contact with the latch. The button is disengaged when the latch is turned to the locked position so the turret can turn normally when the hatch is closed. Once the latch is turned to open the hatch, the button is depressed, and this sends an electric signal to the turret traverse system to suspend the traversal of the turret regardless of any inputs on the control handles and the turret is automatically locked in place.
Besides the hatch, the cupola is fitted with a small array of observation devices. The commander does not have much in the way of surveillance equipment. He is provided with a TKN-3B periscope and two TNPO-180 general purpose periscopes. This is not many, but this is compensated by the fact that the cupola can be rotated a full 360 degrees. The very light weight of the cupola makes it very easy to spin.
The ergonomic qualities of the commander's station are best described as spartan. Being located in the front of the hull next to the engine compartment, the station is longer than it is wide. The width of the "corridor" where the driver and commander is seated is only 60cm, which is quite narrow, but enough for the commander to operate the TKN-3B and swing it around (with elbows tucked in).
Because a one-man turret was specified for the BMP, the commander had to be seated in the hull. directly behind the driver. This was not particularly unusual for an armoured personnel carrier at the time as they typically did not have a two-man turret, if they had a turret at all, but even so, it was not an ideal position for a vehicle commander given that the role invariably involves a great deal of surveillance. The main drawback is that the commander cannot look towards the rear of the vehicle from the 5 o'clock to 3 o'clock sector. Moreover, thanks to a combination of its low height and the relatively small turret, it is easy to camouflage the BMP and place it in a turret defilade position behind natural concealment such as bushes, tall grass and soil mounds, but the commander's view is completely blocked if the vehicle enters a turret defilade position so the gunner must survey the environment alone from his turret station. However, the commander's location in the vehicle does not prevent him from surveying the battlefield when the vehicle is in a hull defilade position as the commander's cupola is slightly raised and has sufficient clearance to allow the periscopes to peek over an obstacle without needing the vehicle to expose its hull.
Ideally, the commander should be located in the turret alongside the gunner as this allows two crew members to search for targets independently from a turret defilade position and it permits the commander to issue orders and designate targets much more effectively. A turret also offers a taller vantage point for a superior range of vision and a turret tends to be on the center of gravity of the vehicle, thus making hull oscillations less obvious. This helps improve ride quality and ease of observation. It also enhances the commander's ability to direct the driver and the convenience of a platoon or company commander to marshal other members of the unit. The advantage of a two-man turret was recognized and subsequent developments discarded the one-man turret concept. For instance, the Object 768 prototype, designed by the in-house design bureau of the ChTZ factory as the intended successor to the BMP-1 in 1972, featured a two-man turret with a 73mm cannon of increased power. This is shown in the photo below (courtesy of the tankmuseum.ru website for the Kubinka tank museum) Additionally, the BRM-1K reconnaissance vehicle based on the BMP-1 also had its commander seated in a large two-man turret and not in the hull.
GUNNER'S STATION
The gunner's resides in the one-man turret. He is responsible for maintaining the machine gun, cannon, sighting complexes, and autoloader. It is rather cramped in the turret, but this is balanced out to some extent by the lack of a turret basket. This means that the gunner can stretch his legs whenever the turret is not moving, and as he controls the rotation of the turret, he is much more able to ensure the safety of his appendages. There is a corridor beside the turret, joining the passenger space and the front hull space where the commander and driver are situated. When not in combat, the gunner can spread his legs out into this space, with the turret locked in traverse to prevent accidents.
The turret floor is a flat sheet of aluminium with level edges except in front of the gunner's seat where the edges are bent upwards to form a shallow ridge. This ridge is there to ensure that the gunner's feet do not slip off the floor. There is also a simple sheet metal shin guard stretching from one of the struts connecting the turret floor to the turret to the ammunition and casing container to the right of the gunner. This shin guard prevents the loader from accidentally putting his knees outside the perimeter of the turret floor. All of this is shown in the photo below, taken by Hans-Hermann Bühling.
The gunner's hatch opens forward and locks in the upright position which is very typical of a Soviet vehicle. If a gunner of average height stands on his seat with the seat in the lowest setting, his head will be just over the edge of the open hatch, so the hatch itself will be able to provide his torso with frontal protection from bullets while the gunner enjoys the better view gained from having a higher vantage point.
Due to the installation of the cannon along the center axis of the turret, the gunner's station is confined to the left half of the turret and the right half of the turret is used for electronic equipment. Components of the 9S428 missile guidance system are installed on the turret wall on the right half of the turret.
The 2A28 "Grom" cannon of the BMP lacks a fume extractor. To remove propellant fumes from the cannon and the coaxial machine gun, the turret has a special ventilator that extracts air from the fighting compartment and expels it out through a vent on the turret roof. The ventilator consists of a single centrifugal extractor fan powered by an electric motor that leads to a vent on the turret roof. There is also a duct that connects the extractor fan inlet to the container on the turret floor for spent propellant charges, thus allowing the system to extract the fumes emitted from these spent charges from propellant residue. The photo below, courtesy of Vladimir Yakubov, shows the extractor fan of the ventilator and the duct that connects the fan inlet to the container on the turret floor.
The BMP-1 technical manual mentions that the extractor fan is the same as the type used in the propellant fume extraction system for the passenger firing ports. Without this system, it would tend to be quite unpleasant to remain confined inside the small turret of the BMP with all the hatches closed during sustained fire. Even when the weapons are not being fired, this vent continues to help circulate air in the fighting compartment.
The gunner is provided with a total of five observation devices in his turret: the 1PN22M1 sight aimed directly forward, and four TNPO-170 periscopes arranged around the perimeter of his hatch. Two of the TNPO-170 periscopes are placed on the flanks of the primary sight to provide forward vision which is helpful for seeing targets and maintaining situational awareness, and the other two are placed on the sides of the hatch to allow the gunner to check his surroundings. There is a dead zone in the 2 o'clock sector because a periscope could not be placed directly behind the breech of the 2A28 "Grom" cannon, as that space was needed for loading the cannon. The photos below shows the layout of the periscopes around the gunner's hatch. Photos by Robert De Craecker.
When a mounting post was installed on the right side of the turret roof in the BMP-1P modernization for the 9P135M missile launcher, it partially obstructed the view from the TNPO-170 aimed to the right.
The front-right periscope can also be used to aim the weapons in the event that the primary sight fails. Engaging targets with the coaxial machine gun can be done by following the tracers for fire correction, and the "Malyutka" missile can be guided by eye at shorter distances. With a total of five observation devices, a BMP-1 gunner has good vision in the forward 180-degree sector of the turret but no rearward visibility whatsoever. To see behind the turret, the gunner can open his hatch or traverse the turret to the left or right by until one of the side-facing TNPO-170 periscopes is aimed to the rear. In an active combat situation or in an NBC-contaminated environment, only the latter option is feasible. The lack of rearward visibility for the gunner when he is buttoned up was addressed on the BMP-2 when a rear-view prism was added to the gunner's hatch.
The good vision from the BMP-1 turret partly compensates for the sub-optimal location of the commander's station and provides the gunner with a high level of independence in target acquisition when the commander dismounts together with the passengers.
For lighting, there is a PMV-71 dome light located on the turret roof to the left of the gunner's hatch and another one on the turret roof on the opposite side, to the right of the autoloader mechanism. The dome light contains a TN-28-10 incandescent lamp that runs on a voltage of 28 volts and consumes 10 W of power. Each PMV-71 dome light has an output of 10 candelas. For a one-man turret, the amount of illumination is quite good. The gunner has access to a master power relay to control the activation of various electrical systems in the vehicle.
Although the BMP has an overpressure ventilation system that is capable of providing sufficient ventilation for all of the occupants, the gunner has the good fortune of being able to open two hatches for additional ventilation - his personal roof hatch, and the missile loading hatch. When the missile loading hatch is open and the vehicle is moving forward, the rush of wind is deflected by the hatch directly towards the gunner much like the vent window of old cars.
The gunner's seat together with its backrest is adjustable in height. A foldable arm guard is installed on the right side of the seat to isolate the gunner from the autoloader mechanism. The top half of the arm guard is folded down to allow the gunner to access the two "Malyutka" missiles stowed in the turret when reloading the missile launcher, and the entire arm guard can be detached from the seat for unobstructed access to the turret interior. The 9V332 control box with its control joystick for the "Malyutka" missile system is folded under the seat when not in use.
With the introduction of the 902V "Tucha" smoke grenade launcher system on the BMP-1P, new control boxes had to be installed. The gunner was provided with a revised master power relay to turn on the "Tucha" electrical system, and a "Tucha" launch control box to select individual grenades to launch.
The 1ETs10M powered gun laying system provides powered turret traverse and gun elevation with satisfactory accuracy using all-electric drives. Gun stabilization was not provided and was never provided to any serially produced BMP-1 variant during its career in the Soviet Army, and later, the Russian Army. The gun can be depressed to -4 degrees and elevated to +30 degrees, but direct fire with the 73mm cannon is only possible from -4 degrees to +15 degrees due to the elevation limits of the 1PN22M1 sight.
The DGN-3 electric motor is the turret rotation drive. It runs on 24 V and has an output of 300 W. The DVN-1 electric motor is the gun elevation drive. It also runs on 24 V and has an output of 65 W. The maximum speeds of turret rotation and gun elevation are slightly higher than of a T-64 and significantly higher than of a T-62 or T-55, and the mechanical precision of the BMP gun laying system should be very similar to these two tanks. As such, the gun laying system was not only more than sufficiently precise to facilitate the use of the 2A28 cannon out to its maximum effective range of 800 meters but it could also be considered quite modern.
Vertical:
Maximum Cannon Elevation Speed: 6° per second
Minimum Cannon Elevation Speed: 0.07° per second
Horizontal:
Maximum Turret Traverse Speed: 20° per second
Minimum Turret Traverse Speed: 0.1° per second
In 1973, the BMP-1 was equipped with the 1ETs10M2 modification of the original powered gun laying system. The new model was adapted to the modification of the autoloader in accordance with the introduction of HE-Frag ammunition for the main gun. The control handles gained a switch to load HE-Frag rounds, or rather, to control the operation of the autoloader so that it selectively loads HEAT rounds if the gunner presses the "K" (HEAT) button, but only rotates the conveyor by one step if the gunner presses the "O" (HE-Frag) button.
The BMP-1 cannot fire on the move with any guarantee of accuracy unless the vehicle is travelling over a well paved road at low speed. Nevertheless, BMP gunners were trained to fire on the move at low speeds using both the 2A28 cannon and the PKT coaxial machine gun. To maximize training time without needing to cover the costs of maintenance and fuel, the training was often done on simulators. These simulators were platforms built into the ground which the BMP would park on. To simulate the experience of driving over uneven terrain, the platform oscillates at various intensities while the gunner uses the coaxial PKT machine gun to engage pop up targets representing infantry.
Video footage of a firing exercise taking place can be found on YouTube on yolkhere's channel, here (link).
The short video and the limited amount of information I have gathered doesn't say if gunners were trained to fire the 73mm cannon from the platform, but as far as I know, it was not part of the curriculum. Live fire training at the firing range was more extensive as it involved both tank and infantry-type targets and tested the coordination of the entire crew, not just the skills of the gunner. This made time on the range irreplaceable, not that further evidence was needed.
Due to the presence of the OU-3GA infrared spotlight on the commander's cupola, a deadzone with an arc of 50 degrees was created. The turret cannot be aimed at the normal angles of gun elevation over this arc, and instead, the gun must be elevated over the spotlight. Another deadzone exists over the rear arc where the gun depression angle over the troop compartment roof is reduced to a maximum of -2 degrees instead of the normal -4 degrees, but this is completely normal for practically all turreted tanks and should not have a significant effect during combat.
The PU-6 control handles are used with this system. The right handle has a thumb button for firing the "Grom" cannon and the left handle has a thumb button for firing the coaxial machine gun.
One of the design requirements stipulated for the BMP was that it had to have a sighting system equal in capabilities to the tanks it was to complement, including a night fighting capability. As a result, the 1PN22 combined day-night sight was developed. The original 1PN22 was only used in the prototype turrets installed on the five competing prototypes that took part in the 1961-1965 military competition. After the competition was won by the Object 765 in 1965, the modernized 1PN22M1 sight was created and used on all serially produced BMPs.
The 1PN22M1 is a relatively advanced sight that features a fixed magnification daytime optic and a night vision channel with a 1st Generation three-stage light amplifier. The gunner looks through the same eyepiece for both the day and night channels, and he can switch between the two channels by rotating an internal mirror. By incorporating two features into one sighting system, Soviet engineers were able to save space inside the small turret and simplify the sighting system without compromising overall effectiveness.
The head of the sight contains a mirror that is linked to the trunnion of the 2A28 cannon. The viewing window of the sight head is protected by a pane of glass, and an additional protective glass pane can be lowered when launching ATGMs to prevent the main viewing window of the sight from being scorched by the rocket exhaust. After the ATGM leaves the launch rail, the scorched glass pane is raised.
The night vision system of the 1PN22M1 sight is housed in the left side and bottom of the sight housing. The left "shoulder" of the sight contains a reflector assembly with one mirror and a prism that projects light collected from the objective lens of the sight into the U-42-M light intensifier tube at the bottom of the sight. The amplified image is then reflected to the eyepiece of the sight through four prisms.
The sight has fixed magnification of 6x and a field of view of 15° in the day channel. The magnification was adequate given the effective range of the main gun and the coaxial machine gun, but from a technical point of view, the capabilities of the sight are exceptional. The magnification power of the 1PN22M1 is directly comparable to that of tanks with larger, high power cannons like the M48, which used the M20 sight with a 6x maximum magnification, though it lacked selectable magnification settings as on the Soviet TSh2 series of sights. With a field of view of 15 degrees, however, the 1PN22M1 provided considerably expanded vision compared to tank sights like the TSh2 series (9 degrees at 7x magnification). The 1PN22M1 offers a notably higher magnification than the PGO-9 periscopic sight used on the SPG-9, which only had a 4.2x magnification with a field of view of 10.5 degrees. This means that a BMP-1 gunner should be able to identify and fire upon targets at a longer range than an SPG-9 gunner, but because the effective range is largely the same, the higher magnification of the 1PN22M1 sight did not give the BMP-1 any major advantage. Needless to say, both the commander and gunner of a BMP-1 have much less visibility when they are buttoned up compared to an SPG-9 crew.
The viewfinder of the sight is abundantly marked for ballistic drop and lead. Windage was adjusted using the lead scales. The small crosshair at the top of the viewfinder is zeroed for 50 meters, so in practice, it serves as a reference point rather than an actual aiming mark. The viewfinder permits aimed fire out to a maximum range of 1,300 meters for both the PG-15V rounds as well as for the PKT coaxial machine gun. A separate scale for the PKT is not needed because it has very close ballistics to the PG-15V round out to 1,300 meters, allowing the gunner to use the range scale for both weapons interchangeably.
The point blank range of the PG-15V round fired from the 2A28 is 765 meters for a target with a height of 2 meters, meaning that up to a distance of 765 meters, the trajectory of a PG-15V round will have a total height of 2 meters. In theory, this means that if the target tank is 2 meters tall and within 765 meters of the BMP-1, the gunner can simply aim his crosshair at the roof of the target and open fire with a total guarantee of achieving a hit at some part of the tank. If the tank is 765 meters away, the shot will impact its lower glacis, and if it is 300 meters away, the shot will impact the turret. However, due to a myriad of factors such as the dispersion of shots, it is still necessary to obtain a range reading to maximize the probability of hit. For this reason, the 1PN22M1 sight features a stadiametric rangefinder in its viewfinder.
The rangefinder scale is intended for a target 2.7 meters in height, starting from 400 meters and ending at 1,300 meters. Below 400 meters, the trajectory of PG-15V rounds is flat enough that the battlesight gunnery technique is sufficiently accurate for achieving a probability of hit exceeding 90%, and fire correction can be accomplished with the burst-on-target gunnery technique if it is truly necessary. There are no range scales between the 50-meter crosshair and the 400-meter range scale. In the stadiametric scale, the target height of 2.7 meters is representative of the height of the average Western tank, including the Chieftain, M48, M60A1, Leopard 1, and even some later combat vehicles like the Marder 1.
The sight is switched to the night vision channel by redirecting the light collected from the objective lens away from the day channel optical assembly to the reflector assembly located in the left side of the sight. The light then passes through one of six light filters on a revolving disc before entering the light intensifier tube at the bottom of the sight. The gunner chooses the filter by rotating the knob at the bottom left of the sight, shown in the drawing on the left below.
The light filters are designed to provide the optimal level of contrast in various lighting conditions, including daylight. The designations of the various filters and their purposes are listed in the table below. Filters 'O' and 'KS-17' are intended for use at night under natural illumination from starlight and moonlight. Filter 'NS-10' is intended for use at twilight. Filter 'NS-11' is intended for use in overcast daylight conditions. Filters 'NS-12-1' and 'NS-12' are intended for use during sunny weather.
The night vision channel has a separate viewfinder reticle design from the daytime channel. The reticle is projected onto the viewfinder using a collimator system with an adjustable brightness. The reticle has greatly simplified lead and range correction scales compared to the day channel reticle. The sight has a fixed magnification of 6.7x and a field of view of 6 degrees in the night channel. As with the day channel, this was excellent performance compared to the tank equivalent. In this case, the standard TPN1 series of night sights, which had a smaller magnification of 5.5x but the same field of view of 6 degrees.
The gunner's hatch opens forward and locks in the upright position which is very typical of a Soviet vehicle. If a gunner of average height stands on his seat with the seat in the lowest setting, his head will be just over the edge of the open hatch, so the hatch itself will be able to provide his torso with frontal protection from bullets while the gunner enjoys the better view gained from having a higher vantage point.
Due to the installation of the cannon along the center axis of the turret, the gunner's station is confined to the left half of the turret and the right half of the turret is used for electronic equipment. Components of the 9S428 missile guidance system are installed on the turret wall on the right half of the turret.
The 2A28 "Grom" cannon of the BMP lacks a fume extractor. To remove propellant fumes from the cannon and the coaxial machine gun, the turret has a special ventilator that extracts air from the fighting compartment and expels it out through a vent on the turret roof. The ventilator consists of a single centrifugal extractor fan powered by an electric motor that leads to a vent on the turret roof. There is also a duct that connects the extractor fan inlet to the container on the turret floor for spent propellant charges, thus allowing the system to extract the fumes emitted from these spent charges from propellant residue. The photo below, courtesy of Vladimir Yakubov, shows the extractor fan of the ventilator and the duct that connects the fan inlet to the container on the turret floor.
The BMP-1 technical manual mentions that the extractor fan is the same as the type used in the propellant fume extraction system for the passenger firing ports. Without this system, it would tend to be quite unpleasant to remain confined inside the small turret of the BMP with all the hatches closed during sustained fire. Even when the weapons are not being fired, this vent continues to help circulate air in the fighting compartment.
The gunner is provided with a total of five observation devices in his turret: the 1PN22M1 sight aimed directly forward, and four TNPO-170 periscopes arranged around the perimeter of his hatch. Two of the TNPO-170 periscopes are placed on the flanks of the primary sight to provide forward vision which is helpful for seeing targets and maintaining situational awareness, and the other two are placed on the sides of the hatch to allow the gunner to check his surroundings. There is a dead zone in the 2 o'clock sector because a periscope could not be placed directly behind the breech of the 2A28 "Grom" cannon, as that space was needed for loading the cannon. The photos below shows the layout of the periscopes around the gunner's hatch. Photos by Robert De Craecker.
When a mounting post was installed on the right side of the turret roof in the BMP-1P modernization for the 9P135M missile launcher, it partially obstructed the view from the TNPO-170 aimed to the right.
The front-right periscope can also be used to aim the weapons in the event that the primary sight fails. Engaging targets with the coaxial machine gun can be done by following the tracers for fire correction, and the "Malyutka" missile can be guided by eye at shorter distances. With a total of five observation devices, a BMP-1 gunner has good vision in the forward 180-degree sector of the turret but no rearward visibility whatsoever. To see behind the turret, the gunner can open his hatch or traverse the turret to the left or right by until one of the side-facing TNPO-170 periscopes is aimed to the rear. In an active combat situation or in an NBC-contaminated environment, only the latter option is feasible. The lack of rearward visibility for the gunner when he is buttoned up was addressed on the BMP-2 when a rear-view prism was added to the gunner's hatch.
The good vision from the BMP-1 turret partly compensates for the sub-optimal location of the commander's station and provides the gunner with a high level of independence in target acquisition when the commander dismounts together with the passengers.
For lighting, there is a PMV-71 dome light located on the turret roof to the left of the gunner's hatch and another one on the turret roof on the opposite side, to the right of the autoloader mechanism. The dome light contains a TN-28-10 incandescent lamp that runs on a voltage of 28 volts and consumes 10 W of power. Each PMV-71 dome light has an output of 10 candelas. For a one-man turret, the amount of illumination is quite good. The gunner has access to a master power relay to control the activation of various electrical systems in the vehicle.
Although the BMP has an overpressure ventilation system that is capable of providing sufficient ventilation for all of the occupants, the gunner has the good fortune of being able to open two hatches for additional ventilation - his personal roof hatch, and the missile loading hatch. When the missile loading hatch is open and the vehicle is moving forward, the rush of wind is deflected by the hatch directly towards the gunner much like the vent window of old cars.
The gunner's seat together with its backrest is adjustable in height. A foldable arm guard is installed on the right side of the seat to isolate the gunner from the autoloader mechanism. The top half of the arm guard is folded down to allow the gunner to access the two "Malyutka" missiles stowed in the turret when reloading the missile launcher, and the entire arm guard can be detached from the seat for unobstructed access to the turret interior. The 9V332 control box with its control joystick for the "Malyutka" missile system is folded under the seat when not in use.
With the introduction of the 902V "Tucha" smoke grenade launcher system on the BMP-1P, new control boxes had to be installed. The gunner was provided with a revised master power relay to turn on the "Tucha" electrical system, and a "Tucha" launch control box to select individual grenades to launch.
POWERED CONTROLS
The 1ETs10M powered gun laying system provides powered turret traverse and gun elevation with satisfactory accuracy using all-electric drives. Gun stabilization was not provided and was never provided to any serially produced BMP-1 variant during its career in the Soviet Army, and later, the Russian Army. The gun can be depressed to -4 degrees and elevated to +30 degrees, but direct fire with the 73mm cannon is only possible from -4 degrees to +15 degrees due to the elevation limits of the 1PN22M1 sight.
The DGN-3 electric motor is the turret rotation drive. It runs on 24 V and has an output of 300 W. The DVN-1 electric motor is the gun elevation drive. It also runs on 24 V and has an output of 65 W. The maximum speeds of turret rotation and gun elevation are slightly higher than of a T-64 and significantly higher than of a T-62 or T-55, and the mechanical precision of the BMP gun laying system should be very similar to these two tanks. As such, the gun laying system was not only more than sufficiently precise to facilitate the use of the 2A28 cannon out to its maximum effective range of 800 meters but it could also be considered quite modern.
Vertical:
Maximum Cannon Elevation Speed: 6° per second
Minimum Cannon Elevation Speed: 0.07° per second
Horizontal:
Maximum Turret Traverse Speed: 20° per second
Minimum Turret Traverse Speed: 0.1° per second
In 1973, the BMP-1 was equipped with the 1ETs10M2 modification of the original powered gun laying system. The new model was adapted to the modification of the autoloader in accordance with the introduction of HE-Frag ammunition for the main gun. The control handles gained a switch to load HE-Frag rounds, or rather, to control the operation of the autoloader so that it selectively loads HEAT rounds if the gunner presses the "K" (HEAT) button, but only rotates the conveyor by one step if the gunner presses the "O" (HE-Frag) button.
The BMP-1 cannot fire on the move with any guarantee of accuracy unless the vehicle is travelling over a well paved road at low speed. Nevertheless, BMP gunners were trained to fire on the move at low speeds using both the 2A28 cannon and the PKT coaxial machine gun. To maximize training time without needing to cover the costs of maintenance and fuel, the training was often done on simulators. These simulators were platforms built into the ground which the BMP would park on. To simulate the experience of driving over uneven terrain, the platform oscillates at various intensities while the gunner uses the coaxial PKT machine gun to engage pop up targets representing infantry.
Video footage of a firing exercise taking place can be found on YouTube on yolkhere's channel, here (link).
The short video and the limited amount of information I have gathered doesn't say if gunners were trained to fire the 73mm cannon from the platform, but as far as I know, it was not part of the curriculum. Live fire training at the firing range was more extensive as it involved both tank and infantry-type targets and tested the coordination of the entire crew, not just the skills of the gunner. This made time on the range irreplaceable, not that further evidence was needed.
Due to the presence of the OU-3GA infrared spotlight on the commander's cupola, a deadzone with an arc of 50 degrees was created. The turret cannot be aimed at the normal angles of gun elevation over this arc, and instead, the gun must be elevated over the spotlight. Another deadzone exists over the rear arc where the gun depression angle over the troop compartment roof is reduced to a maximum of -2 degrees instead of the normal -4 degrees, but this is completely normal for practically all turreted tanks and should not have a significant effect during combat.
The PU-6 control handles are used with this system. The right handle has a thumb button for firing the "Grom" cannon and the left handle has a thumb button for firing the coaxial machine gun.
1PN22M1
One of the design requirements stipulated for the BMP was that it had to have a sighting system equal in capabilities to the tanks it was to complement, including a night fighting capability. As a result, the 1PN22 combined day-night sight was developed. The original 1PN22 was only used in the prototype turrets installed on the five competing prototypes that took part in the 1961-1965 military competition. After the competition was won by the Object 765 in 1965, the modernized 1PN22M1 sight was created and used on all serially produced BMPs.
The 1PN22M1 is a relatively advanced sight that features a fixed magnification daytime optic and a night vision channel with a 1st Generation three-stage light amplifier. The gunner looks through the same eyepiece for both the day and night channels, and he can switch between the two channels by rotating an internal mirror. By incorporating two features into one sighting system, Soviet engineers were able to save space inside the small turret and simplify the sighting system without compromising overall effectiveness.
The head of the sight contains a mirror that is linked to the trunnion of the 2A28 cannon. The viewing window of the sight head is protected by a pane of glass, and an additional protective glass pane can be lowered when launching ATGMs to prevent the main viewing window of the sight from being scorched by the rocket exhaust. After the ATGM leaves the launch rail, the scorched glass pane is raised.
The night vision system of the 1PN22M1 sight is housed in the left side and bottom of the sight housing. The left "shoulder" of the sight contains a reflector assembly with one mirror and a prism that projects light collected from the objective lens of the sight into the U-42-M light intensifier tube at the bottom of the sight. The amplified image is then reflected to the eyepiece of the sight through four prisms.
The sight has fixed magnification of 6x and a field of view of 15° in the day channel. The magnification was adequate given the effective range of the main gun and the coaxial machine gun, but from a technical point of view, the capabilities of the sight are exceptional. The magnification power of the 1PN22M1 is directly comparable to that of tanks with larger, high power cannons like the M48, which used the M20 sight with a 6x maximum magnification, though it lacked selectable magnification settings as on the Soviet TSh2 series of sights. With a field of view of 15 degrees, however, the 1PN22M1 provided considerably expanded vision compared to tank sights like the TSh2 series (9 degrees at 7x magnification). The 1PN22M1 offers a notably higher magnification than the PGO-9 periscopic sight used on the SPG-9, which only had a 4.2x magnification with a field of view of 10.5 degrees. This means that a BMP-1 gunner should be able to identify and fire upon targets at a longer range than an SPG-9 gunner, but because the effective range is largely the same, the higher magnification of the 1PN22M1 sight did not give the BMP-1 any major advantage. Needless to say, both the commander and gunner of a BMP-1 have much less visibility when they are buttoned up compared to an SPG-9 crew.
The viewfinder of the sight is abundantly marked for ballistic drop and lead. Windage was adjusted using the lead scales. The small crosshair at the top of the viewfinder is zeroed for 50 meters, so in practice, it serves as a reference point rather than an actual aiming mark. The viewfinder permits aimed fire out to a maximum range of 1,300 meters for both the PG-15V rounds as well as for the PKT coaxial machine gun. A separate scale for the PKT is not needed because it has very close ballistics to the PG-15V round out to 1,300 meters, allowing the gunner to use the range scale for both weapons interchangeably.
The point blank range of the PG-15V round fired from the 2A28 is 765 meters for a target with a height of 2 meters, meaning that up to a distance of 765 meters, the trajectory of a PG-15V round will have a total height of 2 meters. In theory, this means that if the target tank is 2 meters tall and within 765 meters of the BMP-1, the gunner can simply aim his crosshair at the roof of the target and open fire with a total guarantee of achieving a hit at some part of the tank. If the tank is 765 meters away, the shot will impact its lower glacis, and if it is 300 meters away, the shot will impact the turret. However, due to a myriad of factors such as the dispersion of shots, it is still necessary to obtain a range reading to maximize the probability of hit. For this reason, the 1PN22M1 sight features a stadiametric rangefinder in its viewfinder.
The rangefinder scale is intended for a target 2.7 meters in height, starting from 400 meters and ending at 1,300 meters. Below 400 meters, the trajectory of PG-15V rounds is flat enough that the battlesight gunnery technique is sufficiently accurate for achieving a probability of hit exceeding 90%, and fire correction can be accomplished with the burst-on-target gunnery technique if it is truly necessary. There are no range scales between the 50-meter crosshair and the 400-meter range scale. In the stadiametric scale, the target height of 2.7 meters is representative of the height of the average Western tank, including the Chieftain, M48, M60A1, Leopard 1, and even some later combat vehicles like the Marder 1.
The sight is switched to the night vision channel by redirecting the light collected from the objective lens away from the day channel optical assembly to the reflector assembly located in the left side of the sight. The light then passes through one of six light filters on a revolving disc before entering the light intensifier tube at the bottom of the sight. The gunner chooses the filter by rotating the knob at the bottom left of the sight, shown in the drawing on the left below.
The light filters are designed to provide the optimal level of contrast in various lighting conditions, including daylight. The designations of the various filters and their purposes are listed in the table below. Filters 'O' and 'KS-17' are intended for use at night under natural illumination from starlight and moonlight. Filter 'NS-10' is intended for use at twilight. Filter 'NS-11' is intended for use in overcast daylight conditions. Filters 'NS-12-1' and 'NS-12' are intended for use during sunny weather.
The night vision channel has a separate viewfinder reticle design from the daytime channel. The reticle is projected onto the viewfinder using a collimator system with an adjustable brightness. The reticle has greatly simplified lead and range correction scales compared to the day channel reticle. The sight has a fixed magnification of 6.7x and a field of view of 6 degrees in the night channel. As with the day channel, this was excellent performance compared to the tank equivalent. In this case, the standard TPN1 series of night sights, which had a smaller magnification of 5.5x but the same field of view of 6 degrees.
Night vision was provided by a passive image intensifier system running on a 40 kV power supply. The system utilizes a three-stage image intensifier cascade tube with three S-1 converter tubes. This level of technology was modern for the 1960's.
This type of image intensifier has a gain of 50,000-75,000, meaning that it is capable of amplifying light by 50,000-75,000 times. Such a high gain is necessary for Gen 1 image intensifiers to provide practical passive viewing with starlight illumination alone. In the 1PN22M1 sight, glare and flash protection is provided to preserve the intensifier tubes via the automatic reduction of the input voltage on the converter tubes, which leads to a sharp drop in the gain, as a result of which the tubes are not burned out by a sudden flash of bright light and the smearing effect of light sources is reduced.
This system enabled the gunner to identify and fire upon a tank-type target at a range of up to 400 meters with an ambient light of 0.005 lux. The maximum viewing range was limited by the inherently low resolution of the image generated by a three-stage image intensifier tube. Another tactical limitation of this type of image intensifier system is that although the image at the center was clear, the edges would be distorted, thus effectively reducing the useful field of view. A technical limitation is the low service life of the converter tubes due to the very high operating voltages.
This is the same maximum viewing range of the commander's TKN-3B periscope. At the maximum identification range of 400 meters, the gunner could simply lay the center chevron in the viewfinder on a target and open fire immediately once it is identified and expect a high probability of scoring a first-round hit. When firing at targets at ranges of up to 800 meters, the need for a range estimate arises. This can be done using the reticle markings by comparing its known angular dimensions (in arcminutes) to the dimensions of the image of the target.
As the markings show, the BMP-1 is theoretically capable of engaging targets up to a distance of 800 meters at night using the 1PN22M, but the center chevron is calibrated for 400 meters as that is the distance limit of the night vision system. It is only practical to fire at targets from further than 400 meters if the target is illuminated by natural or artificial means.
1PN22M2 was introduced in 1974. From a technical viewpoint, it is identical to the 1PN22M1 in almost every way. The only functional difference is the addition of a scale for HE-Frag rounds which extends far below the original scale for HEAT rounds due to the low velocity of OG-15V HE-Frag rounds. Around the same time, the PGOK-9 sight with compatibility with HE-Frag rounds for the SPG-9 was introduced.
As you can see in the diagram above, the sight is marked for a maximum direct fire range of only 1,600 meters for HE-Frag. This is the hard limit of the direct fire capabilities of the BMP-1 using OG-15V HE-Frag rounds, and also the maximum range of the rounds.
The BMP mounts the 73mm 2A28 "Grom" low-pressure smoothbore cannon. The cannon has a vertically sliding breech block with a spring-loaded folding shell casing deflector at the end of the breech assembly. The cannon has a total length of 2,180mm and a gun tube length of 2,117mm, which is longer than the gun tube of the SPG-9 despite the recoilless gun having a longer chamber for the larger propellant charge. The width of the 2A28 breech housing is very narrow - only 213mm. The cannon does not have a fume extractor.
The barrel life of "Grom" is 1,250 shots. The cannon can elevate between -4 degrees to +30 degrees, but direct fire is only possible from -4 degrees to +15 degrees due to the elevation limits of the 1PN22M1 sight. The breech block can be manually opened with a cam operated by a lever handle located underneath the casing deflector, as shown in the photo below. A recoil guard is attached to the lever.
"Grom" is incredibly lightweight, weighing only 115 kg on its own. Of course, its weight is not so impressive when compared to the SPG-9, which weighs 49.5 kg with its direct fire sight and without its tripod and aiming mechanism. This was mainly due to the need for a recoil mechanism and a breech to withstand the chamber pressure. When installed inside the BMP-1 turret, the full gun assembly includes the cast steel gun mantlet, the "Malyutka" missile launch platform on top of the recoil buffer sleeve, and a set of rollers for aligning the top of the gun breech with the missile launch platform.
As the markings show, the BMP-1 is theoretically capable of engaging targets up to a distance of 800 meters at night using the 1PN22M, but the center chevron is calibrated for 400 meters as that is the distance limit of the night vision system. It is only practical to fire at targets from further than 400 meters if the target is illuminated by natural or artificial means.
1PN22M2
1PN22M2 was introduced in 1974. From a technical viewpoint, it is identical to the 1PN22M1 in almost every way. The only functional difference is the addition of a scale for HE-Frag rounds which extends far below the original scale for HEAT rounds due to the low velocity of OG-15V HE-Frag rounds. Around the same time, the PGOK-9 sight with compatibility with HE-Frag rounds for the SPG-9 was introduced.
As you can see in the diagram above, the sight is marked for a maximum direct fire range of only 1,600 meters for HE-Frag. This is the hard limit of the direct fire capabilities of the BMP-1 using OG-15V HE-Frag rounds, and also the maximum range of the rounds.
2A28 "GROM"
The BMP mounts the 73mm 2A28 "Grom" low-pressure smoothbore cannon. The cannon has a vertically sliding breech block with a spring-loaded folding shell casing deflector at the end of the breech assembly. The cannon has a total length of 2,180mm and a gun tube length of 2,117mm, which is longer than the gun tube of the SPG-9 despite the recoilless gun having a longer chamber for the larger propellant charge. The width of the 2A28 breech housing is very narrow - only 213mm. The cannon does not have a fume extractor.
The barrel life of "Grom" is 1,250 shots. The cannon can elevate between -4 degrees to +30 degrees, but direct fire is only possible from -4 degrees to +15 degrees due to the elevation limits of the 1PN22M1 sight. The breech block can be manually opened with a cam operated by a lever handle located underneath the casing deflector, as shown in the photo below. A recoil guard is attached to the lever.
"Grom" is incredibly lightweight, weighing only 115 kg on its own. Of course, its weight is not so impressive when compared to the SPG-9, which weighs 49.5 kg with its direct fire sight and without its tripod and aiming mechanism. This was mainly due to the need for a recoil mechanism and a breech to withstand the chamber pressure. When installed inside the BMP-1 turret, the full gun assembly includes the cast steel gun mantlet, the "Malyutka" missile launch platform on top of the recoil buffer sleeve, and a set of rollers for aligning the top of the gun breech with the missile launch platform.
Rounds are fired electrically, with a mechanical striker as a backup.
The recoil mechanism consists of a hydraulic recoil buffer and coil return spring. It is wrapped around the base of the barrel and encased in an armoured sleeve, so it is concentric to the bore axis of the cannon. This is a positive influence on the dispersion characteristics of the cannon. Owing to its low operating pressure and its compact overall design, the "Grom" has a recoil stroke of only 150mm.
As the drawing below shows, the trunnion and barrel chamber of the "Grom" are at the same location, and because the BMP-1 turret has a protruding gun mount with the trunnion located in front of the turret ring, the cannon only protrudes a short distance into the turret and only the breech can be seen from inside the turret.
The recoil buffer sleeve also has built-in provisions for mounting the "Malyutka" launching rail. When a missile is mounted on the launcher, the cannon becomes somewhat unbalanced by the weight. The missile itself weighs 10.9 kg and it is located forward of the gun trunnion, making the gun rather front-heavy.
Even back in 1966, it was a somewhat unusual decision to use a low-velocity cannon in lieu of the typical heavy machine gun or autocannon as was normal for both purpose-built IFVs as well as APCs pressed into service in the IFV role. The convention that was followed by foreign militaries at the time was based on relatively sound reasoning: in a typical skirmish where tanks do not need to be involved, an armoured troop carrier should only face light resistance, and indeed, the ACAV modification of the M113 that was used by U.S forces and the ARVN during the war in Vietnam was only armed with externally-mounted M2 and M60 machine guns with gun shields for protection, and this was deemed to be enough for shock action against light infantry. In most cases, even a basic M113 was effective when the opposition was armed only with small arms and small numbers of anti-tank weapons. If additional firepower is desired for a vehicle intended for the same role, a rapid-fire autocannon would be more efficient at dispatching infantry, soft-skinned targets and lightly armoured vehicles compared to a large caliber semi-automatic cannon, but a rapid-fire autocannon has a lower efficiency against dugouts and field fortifications.
From this, it is evident that the BMP-1 was largely incapable of countering man-portable ATGMs which is a noteworthy drawback as the BMP-1 entered service during an era when such weapons were prolific. The effectiveness of the "Grom" in this role was increased when OG-15V HE rounds were introduced, but even so, another limitation came in the form of the rather short 1,600-meter maximum range of the OG-15V round.
If the BMP is being used to supplement a breakthrough attempt, it will not be the centerpiece of the attack. Soviet field manuals detail a number of formations to be used against enemy forces in certain situations, and in one of these, it is stated that when tanks are available to support the advance, one tank can be attached to each motorized infantry platoon. The three BMPs of the platoon follow the tank at a distance of 100 to 200 meters, with either dismounted or mounted infantry. The tank will take care of the toughest targets with its cannon, and the BMPs will knock out anti-tank weapons and lightly armoured vehicles in support of the tank. When a motorized infantry platoon with BMPs is operating without tank support, the modest capabilities of "Grom" would be the most potent anti-armour weapon available to the platoon besides the integrated "Malyutka" missile, so avoiding contact with enemy tanks is a priority. If enemy tanks are not encountered, the 73mm cannon will prove most useful against hardened field fortifications, buildings, and fixed weapon emplacements like machine gun and recoilless rifle nests, and so on. The penetration and blast effect of its HEAT grenades would be particularly useful on fortifications that are otherwise completely immune to machine gun fire, like a triple layer of sandbags (a common standard during the Vietnam war) or a double layer of sandbags reinforced with timber.
Given that the light weight of the BMP-1 allows it to be deployed where tanks cannot go, the firepower of a 73mm cannon becomes particularly meaningful for the troops that are deployed together with the vehicle. From this perspective, there were clear merits to the use of the 73mm "Grom" in the BMP-1. Indeed, there are are a multitude of valid reasons why a weapon like "Grom" is preferable for the BMP rather than a heavy machine gun or a rapid fire autocannon. For one, the firepower of a large caliber cannon is indispensable in many situations. The need for such weapons was met in Vietnam by configuring the M113A1 ACAV with a pintle-mounted 106mm M40A1 recoilless rifle to be operated from the passenger compartment roof hatch. The M113 ACAV with the M40A1 had tremendous firepower but the vehicle provided no protection whatsoever for the gunner and had a severely constrained rate of fire due to the small roof hatch of the passenger compartment and inconvenient location of the weapon itself; the rear of the gun tube extended behind the roof hatch, so the loader has to contort himself to fit each cartridge - almost a meter long and weighing 16.4 kg - through the breech. It was also unsafe for personnel to stand behind or even near the vehicle when the M40A1 is in use due to the colossal back blast and firing signature. The British FV432 "WOMBAT" had an even more powerful 120mm L6 "WOMBAT" recoilless rifle mounted in a layout similar to the M113 and thus shared the same fundamental shortfalls, exacerbated by the more massive size (more than 1.1 meters) and weight (27.2 kg) of the cartridges. As such, these vehicles were tactically distinct from the BMP-1 and neither of the two were proper analogues.
The British Alvis Saladin armoured car and FV101 Scorpion reconnaissance vehicle were both armed with 76mm low pressure guns in fully enclosed turrets, and the Australian Army developed a closer analogue of the BMP-1 in 1967 by mating the fully enclosed turret of the Saladin armoured car with a 76mm L5A1 low pressure gun to the hull of the M113A1, thus creating the Saladin FSV (Fire Support Vehicle). The Saladin FSV is shown in the photo belo. In continuation of this concept, the MSV was created in 1976 by mating the turret of a Scorpion with its 76mm L23 low pressure gun to the M113A1. But even so, these were still fire support vehicles and not pure IFVs. The BMP-1 was completely unique in its combination of traits in 1966 and for better or worse, remained unique throughout the remainder of the Cold War.
From the perspective of the Bundeswehr, the decision to mount the 20mm HS.820 on the SPz 12-3 and the 20mm Rh202 on the Marder was motivated by the need for sufficient firepower to deal with dismounted infantry and lightly armoured troop carriers. In the Soviet Army, this need was met by using a combination of a 14.5mm KPVT heavy machine gun and a 7.62mm SGMT or PKT general purpose machine gun. This armament scheme was established as the standard armament of Soviet armoured personnel carriers and armoured cars beginning with the BRDM-2 (1962) and the BTR-60PB (1966) which both used the same BPU-1 turret. The KPVT would be used against armoured personnel carriers - such vehicles would typically only have limited protection from 12.7mm machine guns - and infantry behind solid obstacles, and the SGMT or PKT would be used against infantry in the open. Although the KPVT was not as useful in the anti-personnel role as a 20mm or 23mm rapid-fire autocannon as its caliber is too small to deliver an effective explosive payload, it fulfilled the same niche in every other respect and was more than adequate for armoured personnel carriers. With this in mind, an escalation in firepower to encompass tanks as the primary target for an IFV like the BMP-1 is not unusual.
According to the firing table for the PG-9 grenade fired from the 2A28 cannon, the technical dispersion of the PG-9 grenade is 0.6 mils in both the horizontal and vertical axes. The technical dispersion of the OG-9 grenade fired from the 2A28 is 0.9 mils in the horizontal axis and 1.0 mil in the vertical axis.
The point blank range of the cannon with PG-9 HEAT grenades against a medium tank target with a height of 2.7 meters is 800 meters. Theoretically, this allows the gunner to neglect the range estimation process and open fire immediately at a tank within 800 meters with a reasonable expectation of scoring a first-round hit, but due to the dispersion of each shot, the reality is that range estimation is still required to achieve a reasonable probability of hit.
According to comparative data published in the book "БМП-1 (1964-2000): Боевая машина пехоты" by Sergey Malyshev, a basic BMP-1 only has a 35% chance of eliminating an ATGM team with two shots from its cannon at a range of 500 meters. This drops to a measly 10% at a range of 1,000 meters. For comparison, a 30mm autocannon (the 2A72 in this case) has a 100% chance of eliminating an ATGM team with sixteen shots at 500 meters, 50% chance at 2,500 meters, and 40% chance at a range of 4,000 meters. In this comparison, both vehicles are stationary. Against ground targets, the main downside of the 73mm HEAT rounds fired from the "Grom" is that they have an extremely limited fragmentation effect and the explosive charge is not powerful enough to ensure the elimination of soft-skinned targets in the open unless it detonates close to the target.
According to the same book, the probability of destroying an armoured personnel carrier with two shots from the 2A28 cannon is 80% at a range of 500 meters. This drops to only 25% at a range of 1,000 meters. Keep in mind that the probability of destruction is not the same as the probability of hit, as each hit is not guaranteed to destroy the target.
Zaloga claims that the "Grom" can achieve a 70% hit rate on a stationary tank-type target at 500 meters in still air, degrading to 50% at 800 meters. This is not high compared to a high velocity tank cannon, but still quite respectable, as this is already somewhat close to the performance level of the T-62 firing 3UBK-3 115mm HEAT shells, as you can see in the TRADOC bulletin diagram below. An M60A1 could achieve an 80% hit rate with its own 105mm HEAT shells at the same range thanks to its optical coincidence rangefinder.
Without knowing the target that was used to determine the probability of hit data supplied by Zaloga, it is not possible to make any firm conclusions. Nevertheless, the ineffectiveness of the "Grom" cannon at long range is hardly a secret, and its maximum effective range of 800 meters may not even be achievable in practice. During one a live firing trial, a BMP-1 was made to open fire against a stationary T-55 tank at 800 meters. Out of 50 shots, only 17 hit the tank; the others were carried off their trajectory by the wind. This translates to a 34% hit rate.
Nevertheless, it is worth pointing out that a T-55 is smaller than a typical NATO tank. The British Chieftain tank, for example, is 2.9 meters tall and 3.66 meters wide. The American M60A1 has a similar height of 2.9 meters (not counting the very large commander's cupola) and 3.63 meters wide. The German Leopard 1 was 2.6 meters tall and 3.25 meters wide while the French AMX-30 was by far the smallest at 2.52 meters in height and only 3.1 meters in width. The T-54 is only 2.4 m tall and 3.37 m wide. The probability of hit will be higher at all ranges against a larger target, and vice versa. Therefore, it can be inferred that the "Grom" has a slightly higher than 50% chance of hitting a stationary M60 or Chieftain at a distance of 800 meters under favourable weather conditions when using the standard PG-15V HEAT round. The gunner will have to rely more on the ATGM when engaging tanks at distances exceeding 800 meters, and will become totally dependent on the ATGM when fighting at distances of more than 1,300 meters.
As a fighting system, the "Grom" cannon was the most potent direct fire weapon organic to a motorized infantry squad equipped with a BMP-1. An RPG-7 with five grenades would be carried by the grenadier in the squad and it would be operated together with the assistant grenadier. The RPG-7 was a powerful weapon in its own right, but it belonged to a different class than that of the "Grom". The penetration power of the original 85mm PG-7V grenade from 1961 was also less compared to the 73mm PG-9 fired by the "Grom" - 260mm RHA compared to 300mm RHA. In 1969, the improved 70mm PG-7VM grenade entered service with a warhead derived from the PG-9 and a modified propulsion system. The deflection of the projectile from crosswinds was decreased by 1.5 times and the accuracy of fire was increased by around 20-25%. But even with these improvements, the probability of hitting targets beyond 300 meters was still a challenge.
A further examination of the functional precision of the PG-7V rocket grenade when fired from an RPG-7 against tank targets can be found in "Analysis of Rocket-Assisted Aspects of Infantry Antitank Weapons" by Dr. Thomas H. Dawson published in the November-December 1975 issue of the Army Research and Development News Magazine. The article details the technical aspects of the PG-7V rocket itself and considers its advantages and disadvantages, concluding that the drawback of increased wind deflection of the rocket design is completely overshadowed by the greatly reduced margin of error allowed in range estimations due to the increased velocity. It was found that compared to a conventional projectile with a muzzle velocity of 100 m/s, a rocket-assisted grenade like PG-7V with a boosted velocity of 300 m/s decreases the angular elevation (range estimate) error by a factor of more than 10, while the angular deflection (crosswind) error increases only by 3 times.
The hit probability data presented in the graph below shows the probability of a PG-7V grenade achieving a first round hit on a 2.3 x 2.3 meter square target with the same nominal ranging error of 15% (stadia rangefinder), technical shot dispersion of 2 mils, and the same crosswind of 3 m/s. Compared to a hypothetical conventional grenade with a muzzle velocity of 100 m/s and no rocket booster, the effective range of the PG-7V - defined as the distance at which a 50% hit probability is achieved - is twice that of the conventional grenade. The hit probability of PG-7V reaches 80% at a range of 140 meters, and it is 20% at 300 meters.
This shows that in a worst-case scenario where a crosswind is present, the effective range of the rocket-assisted grenade is 2 times better than the conventional grenade. When a crosswind is not present, the advantage of the rocket-assisted grenade is even larger.
This is corroborated by data on the number of shots needed to "defeat" an armoured target in various situations is detailed in page 58 the manual "Наставление по стрелковому делу Ручной противотанковый гранатомет РПГ-7, РПГ-7Д " (Manual on the Matters of Firing Hand-held Anti-tank Grenade Launcher RPG-7, RPG-7D) from 1972. The manual does not specify the type of armoured target or the definition of "defeat", but it can be reasonably assumed that the figures refer to the number of shots needed to hit a tank rather than the number of shots needed to kill a tank, as multiple direct hits are usually needed to knock out a postwar tank. Three types of targets are specified: a frontal aspect of a target moving at 20 km/h, a profile target moving at 20 km/h, and a target situated in a hull-down position.
At 100 meters, both the original PG-7V round and the improved PG-7VM round needed only one shot on the frontal aspect of a target moving at 20 km/h, one shot is needed on the profile of a target moving at 20 km/h, and one shot is needed for a tank in a prepared hull-down position. When the distance increases to 200 meters, the number of PG-7V rounds needed increases to two for the frontal target and four for the hull-down target, and the higher precision of the PG-7VM round begins to show itself as only three shots are needed for the hull-down target. The gap in accuracy between the PG-7V and the PG-7VM widens as the distance increases, but the limits of the RPG-7 are quite evident as the PG-7VM round achieves a 50% hit probability for the front silhouette and side silhouette of moving tanks at just 200 meters and 300 meters respectively. For comparison, the Carl Gustaf M2 (m/48) achieves the same hit probability against a moving tank at a range of 150 meters.
In a best-case scenario where the target is a static tank and there is no crosswind, the effective range where the RPG-7 achieves a 50% hit probability reaches 250 meters. The Carl Gustaf M2 (m/48) achieves the same hit probability at a range of 200 meters. The difference can be attributed to the difference in the flight velocities of the grenades fired by the two antitank systems. The RPG-7 launches a rocket-assisted grenade at a muzzle velocity of only 140 m/s but the projectile accelerates to a peak velocity of 300 m/s after it leaves the launcher, after which it starts to decelerate. The Carl Gustaf launches its HEAT grenade at a muzzle velocity of 255 m/s and the grenade experiences a continuous deceleration until it reaches the target.
At a range of 250 meters, "Grom" has a 90% chance of hitting a stationary tank-type target with its PG-9V grenade. Compared to the RPG-7 carried and operated by the anti-tank grenadier in the squad transported in a BMP-1, the maximum effective range of the "Grom" against a tank-sized target is up to three times higher. Most of the difference can be attributed to the much higher velocity of the PG-9V grenade: the muzzle velocity of the PG-9V is 400 m/s m/s and the maximum velocity is 665 m/s. In comparison, the PG-7VM round remains subsonic throughout its entire flight. The probability of hit with an RPG-7 was therefore much more sensitive to errors in range estimates and it was additionally affected by operator stance, which is a factor that is not relevant for a tripod-mounted weapon like the SPG-9 or the vehicle-mounted "Grom".
In other words, the short effective range of the "Grom" was not a problem when considering the full suite of weapons on the BMP-1 in its totality.
The cannon is fed with 40 rounds of ammunition by an autoloader mechanism, all of which is stored in a crescent-shaped conveyor. No additional ammunition was carried in reserve stowage racks. The electrically powered autoloader conveyor is designed to ensure a continuous supply of ammunition for the autoloader.
The conveyor is essentially a chain with external spokes where the 73mm rounds are attached. The drive sprocket, shown in the drawing on the left below and in the photo on the right below, is directly behind the gunner's seat. The electric motor for the conveyor is installed in the turret.
The rocket engine is located at the rear of the projectile, in front of the folding stabilizer fins. Rocket propellant is contained inside the cylindrical segment at the middle of the projectile and the exhaust gasses exit from a Venturi nozzle at the rear end of the projectile, unlike an RPG-7 rocket where multiple exhaust nozzles are arranged around the circumference of the rocket just behind the grenade warhead. A raised lip in front of the stabilizer fins acts as a bore obturator.
Due to the low pressure of the PG-15V round and its low muzzle velocity, the acceleration forces during the launch of the PG-9 grenade were relatively tame. This allowed the thickness of the warhead casing to remain thin and thus allow the diameter of the shaped charge to be maximized. However, the grenade could still acquire a relatively high velocity of 665 m/s thanks to its rocket booster. This allowed it to have a point blank range of 765 meters for a target with a height of 2 meters. For comparison, the BR-350B APBC shell fired from the 76.2mm D-56T gun of the PT-76 had a muzzle velocity of 655 m/s and a point blank range of 780 meters against a target with a height of 2 meters, so it had a marginal point blank range advantage of just 15 meters over the PG-15V. This was due to the lower drag forces experienced by the APBC shell compared to the finned PG-9 grenade. However, when comparing the PG-15V to the 76.2mm BK-354(M) HEAT shell which had a muzzle velocity of just 550 m/s and a point blank range of 630 meters for a target that is 2 meters tall, the relationship is reversed and the PG-15V gains a considerable point blank range advantage.
In other words, the use of rocket assistance technology allowed Soviet engineers to create a HEAT grenade that had superior ballistic performance to a 76.2mm HEAT shell fired from medium-pressure gun while having superior armour penetration performance.
The PG-9 warhead has a conical shaped charge liner made from 40Kh low alloy steel which is widely used for structural purposes where increased strength is required. Compared to a shaped charge with a copper liner, the effectiveness of a steel liner in penetrating armour is somewhat lower, but the post-perforation effect tends to be substantially greater owing to the larger diameter of the penetration cavity. According to a drawing from a January 1997 edition of "Projectile and Warhead Identification Guide", the shaped charge cone has a diameter of 61.7mm and an apex angle of 60 degrees. The liner has a variable thickness, from 1.27mm near the rim to 1.02mm at the apex. The warhead has 258mm of built-in standoff distance between the shaped charge and the tip of the fuze. The use of a variable thickness liner and a wave shaper was a highly advanced feature for a 1962 grenade, as most foreign HEAT shells of the time still lacked even a wave shaper.
The casing of the PG-9 grenade is made from aluminium and weighs only 0.9 kg. A light aluminium casing is exceptionally poor at fragmentation compared to the typical steel casings of tank-fired HEAT shells, and indeed, thin aluminium casings are used in offensive hand grenades like the RGN grenade for this reason. The poor fragmentation effect makes the PG-9 highly anemic against dispersed infantry on open ground, but the 0.322 kg explosive charge can still cause significant damage to light fortifications as it is equivalent to a 0.515 kg TNT charge. In practice, the actual blasting effect should be stronger than the explosive weight alone suggests, because according to studies such as "The analysis of the equivalent bare charge of aluminum cased charge exploding in confined space", the reactivity of aluminium casings on TNT charges increases the total energy of the explosion by 18-26%. The combustion of aluminium particles among the other detonation products acts as a fuel additive, increasing the heat of the explosion and thus enhancing the blast loading.
The PG-9V grenade uses the VP-9 piezoelectric point-initiating, base-detonating (PI-BD) fuze. It features an inertial safety mechanism and it has a self-destruct system that automatically detonates the grenade 4-6 seconds after it is armed. The fuze is armed at a distance of 2.5 to 20 meters from the muzzle of the gun by the braking force of the deceleration from air resistance and the deploying stabilizer fins on the grenade. The nose fuze is connected to the base detonator by the aerodynamic fairing connecting the warhead to the fuze, and an internal conductive cone, which links the positive terminal of the element to the negative terminal of the base detonator via the shaped charge cone. On impact with an obstacle, the mechanical stress induced in the piezoelectric element is converted into an electrical current. The current travels down the conductive cone and shaped charge liner, and into the base detonator, setting off the warhead.
Maximum Chamber Pressure: 73 MPa
Total Cartridge Mass (incl. propellant charge): 3.49 kg
Ballistically, the OG-9 grenade is similar to a mortar shell. It is significantly heavier than a PG-9 grenade and it lacks a rocket motor. Because of this, it is subsonic, with a muzzle velocity of just 290 m/s. Unlike the four long flip-out stabilizing fins of the PG-9 rocket grenade, the eight stabilizing fins on the OG-9 have a much smaller wingspan and gives the grenade the ballistics of a mortar bomb fired at a full charge. Firing tables show that in a 10 m/s crosswind, an OG-9 grenade is deflected by 3 meters.
The OG-9 warhead uses the GO-2 point-detonating fuze. It has an inertial arming mechanism. It is armed by the deceleration experienced by the projectile from air resistance when it leaves the gun, ensuring that the warhead is only armed at a minimum distance of 2.5 meters from the muzzle. The GO-2 fuze is covered by a safety cap that can be removed by the gunner prior to firing.
Although the OG-9 grenade is primarily intended for the anti-personnel and anti-fortification role, they can also be effective against lightly armoured vehicles and soft-skinned vehicles under certain conditions. The photo on the left is from the 15th Artillery Field Regiment website and shows an M113 hit by a B40 anti-tank grenade launcher (RPG-2 clone). The photo on the right is from the Australian War Memorial website and shows a destroyed Australian M113A1 from the Vietnam War. According to the AWM, the vehicle was hit three times by 75mm recoilless rifles during Operation Bribie on the 17th of February 1967. In both photos, it is simple to deduce that the large breaches in the armour were caused by an external explosion because the edges of the armour plate around the breach are bent inward. This implies that the explosive payload of grenades in the 70-80mm caliber range is already sufficient to cause serious damage to lightly armoured vehicles.
The second example is the most interesting because one of the 75mm recoilless rifle rounds struck the passenger compartment roof hatch which was open at the time, and the damage done by the HEAT grenade to the 38mm-thick hatch can be clearly seen. The engine of the M113A1 was destroyed by another round from recoilless rifles. Note that the 75mm M309 HE grenade fired from the M20 recoilless rifle only has 0.676 kg of TNT as its explosive filler and the projectile is launched at a muzzle velocity of just 302 m/s, and the HEAT grenade has even less explosive power. The OG-9 grenade is launched at practically the same muzzle velocity but the explosive charge of its warhead is equivalent to 1.15 kg of TNT. The heavier steel casing of the M309 is irrelevant in this comparison as it is the blasting power of the shell that caused the damage to this M113 and not fragmentation.
Although HEAT rounds are usually the ammunition of choice when grenadiers are facing armoured vehicles, it is clear that even medium-caliber high explosive shells launched at low velocities can cause enough damage to knock out armoured personnel carriers and other vehicles with a similar level of armour protection. With this in mind, it should be understood that the addition of HE rounds as a new ammunition type to the repertoire of the BMP-1 in 1974 did not necessarily result in a trade-off of anti-armour capabilities in exchange for enhanced anti-personnel and anti-fortification capabilities. Rather, the overall firepower and flexibility of the BMP-1 saw a general increase.
The OG-15VM grenade became available later on. It was an improved version using a more powerful A-IX-2 explosive charge instead of A-IX-1. This improved the blasting power of the warhead and added an enhanced incendiary effect.
Although the coaxial machine gun in most IFVs is usually sidelined in favour of their more powerful autocannons when engaging infantry, the BMP is often forced to depend on its PKT when dealing with infantry in the open due to the weak fragmentation effects of the 73mm HEAT grenades. The PKT is mounted to the right of the 73mm 2A28 "Grom" cannon, as it feeds from the right and ejects to the left.
Armour piercing incendiary rounds and armour piercing incendiary tracer ammunition is usually loaded in a 4:1 ratio. The PKT machine gun has a cyclic rate of fire of 650 rounds per minute, and it has a thicker barrel than the infantry-based PK to allow for longer periods of sustained fire. There are two ways to fire the PKT: the left thumbs witch on the control handles, or by depressing the manual trigger lever on the back of the machine gun, on the firing unit just behind the disassembly button.
In 1969, the PK was replaced by the PKM and the corresponding sub-variants were also replaced with modifications of the PKM, including the replacement of the PKT with the PKTM. The PKTM is mainly distinguished from the earlier PKT by the smooth barrel as opposed to the fluted barrel of the PKT. Internally, the PKTM and the PKT differ in the same way that the basic PK and PKM models differ.
The 9M14 "Malyutka" missile entered service in 1963 as part of the 9K11 system. At the time of the introduction of the BMP-1, the 9K11 "Malyutka" ATGM system was already widespread in the Soviet Army as an infantry-operated system and it posed a a very serious threat to NATO armour despite the inherent limitations of its manual guidance principle. Owing to its high performance characteristics despite its dimunitive size, it was viable for both infantry and mounted systems, including dedicated missile carriers, but for the BMP, the most significant aspect was that it was the first ATGM system to be comprehensively incorporated as part of the primary armament of this class of combat vehicle. This was one of the reasons why the BMP-1 is often said to be more qualified as the first true IFV instead than the Schützenpanzer 12-3 which came much earlier, despite the fact that the Bundeswehr had developed mechanized infantry tactics centering on the IFV concept to go with the SPz 12-3 before the Soviet Army. Even the Marder 1 that entered service years after the BMP did not feature an ATGM launching capability.
When the BMP-1 entered service in 1966, the original 9M14 missile had been replaced by the improved 9M14M "Malyutka-M". In a 1966 manual for the BMP-1 (Object 765 sp.1), the 9M14M is the specified model in a standard combat load and the descriptions and instructions in the manual all pertain to the 9M14M only, with no mention of the 9M14 whatsoever. Although the older 9M14 could be fired from the BMP-1 without any compatibility issues, it is safe to assume that it was not officially issued to the BMP-1 during its service in the Soviet Army. The "Malyutka" series and its technical details are described in a separate Tankograd article, "Soviet ATGMs".
Owing to the demanding requirements set forth in a government decree on July 6, 1961, the 9M14 "Malyutka" missile that entered service in 1963 surpassed all of its foreign counterparts. One of the requirements was for the missile to have a weight of 8-10 kg to ensure that it could be transported easily by infantry anti-tank teams, and although the final product went slightly over the limit with a weight of 10.9 kg, it was still light enough for the specified role. Moreover, its relatively small dimensions and foldable fins made it much more convenient to transport, especially in fully enclosed vehicles where compactness was a particularly important factor. The closest counterpart to the 9M14 was the French ENTAC missile, which is comically oversized and overweight in comparison with the more sophisticated "Malyutka" despite belonging to the same class of ATGM.
When installed on the launcher atop the 2A28 cannon and deployed for launch, the 9M14M missile on the BMP-1 is completely exposed and may be damaged. The lack of protection from gunfire and shell fragments was an important consideration, but it was also recognized that the missile could potentially be rendered inoperable in mundane accidents such as in a collision with a tree branch that causes one of the plastic stabilizer fins to break.
To prevent this type of damage, it was officially forbidden for BMP-1 gunners to keep a missile deployed on the external launcher indefinitely. When going on a march, the launcher would be kept empty and all missiles would be stowed internally. The gunner would only load a missile onto the launcher if it was necessary during combat or if combat was imminent and there was a perceived need.
The missile comes assembled with a lightweight launch rail that fits onto the launcher on top of the cannon barrel. It is the same launch rail used in the 9P110 and 9P133 tank destroyers. After a missile is launched, the launch rail remains on the launch platform and it must be manually removed by the gunner before the next missile is loaded. The launch rail would be reused when replenishing the ammunition supply of the vehicle. New missiles are attached to the launch rail before they are stowed in the BMP.
The "Malyutka" launch platform contains electrical connectors that joins the missile guidance system to the missile guidance wire through the launch rail. The missile guidance wire not only transmits steering commands from the operator's joystick to the missile, but also serves as an electrical conduit that supplies the missile with electrical power. The launch platform positions the launch rail at an elevation angle of 3.25 degrees.
During the launch and throughout the flight of the missile, it maintains a spin rate of 8.5 revolutions per second. Although the performance of shaped charge warheads is negatively affected by spin, this modest rate of spin was far too low to have a noticeable effect on the performance of the missile warhead.
Among the requirements for the 9M14 missile was that it must penetrate between 180-200mm of RHA steel at an angle of 60 degrees. The final warhead design managed to achieve a penetration of 200mm RHA, which makes it a direct equivalent to the 9M17P "Fleyta-P" missile. Despite the 9M17P having a larger warhead diameter of 142mm, the smaller 125mm warhead of the "Malyutka" could match its performance thanks to a much larger standoff distance built into the missile fairing.
When launching a missile, the cannon should be elevated to provide the necessary ground clearance to allow the missile to stabilize during flight. The correct elevation is achieved by the gunner placing the crosshair at the bottom of the 1PN22M1 sight viewfinder on the desired target.
Control of the "Malyutka" missile is achieved using the 9S428 control system which includes the analogue electronic components of the control joystick for the gunner and the electrical connections that connect the missile to the launching system on top of the barrel of the "Grom" cannon.
Control of the "Malyutka" missile is MCLOS only, and that means that the gunner must steer the missile manually as it flies through the air. This is done via the 9V332 missile systems control box, which has a joystick to steer and a button to launch the missile. When not in use, the joystick is retracted inside the control box. The 9V332 missile systems control box was originally designed for the 9P110 tank destroyer. The box has a non-functioning dial that was originally meant to allow the 9P110 missile operator to select a missile from the six available on the overhead launch rails. As the BMP-1 can only mount one missile at a time, the dial is permanently set at the number one position. To launch a missile, the gunner presses the "launch" button on the left of the control box. The purple bulb in the center of the box is the missile status indicator. If the bulb does not light up, it means that the missile is either not mounted, not mounted properly, or malfunctioning.
To use the control box, the joystick is extended first. For the best results, the joystick is grasped with both hands and the gunner presses his thumbs against the tip of the joystick to input small corrections when steering the missile. When the joystick is deflected in the four cardinal directions, the missile acquires a directional acceleration corresponding to the deflection angle of the joystick. For example, if the joystick was merely tapped to the left, the missile accelerates a small amount to the left, and if the joystick was pushed to its maximum deflection to the left, the missile accelerates very quickly to the left. The missile maintains its speed after it is steered, so if the gunner returns the joystick to the neutral position, the missile will continue to drift in the direction it was previously steered. The gunner must input a correction in the opposite direction to return the missile to a straight trajectory.
When a missile is in flight, the gunner is supposed to concentrate on guiding the missile to the target but there are no technical limitations that prevent the gunner from firing the 2A28 cannon or the coaxial machine gun. The missile control system and the turret controls are not linked.
The control box is installed on a hinged pedestal. When not in use, the box is stowed away by swinging the pedestal underneath the gunner's seat.
The 9M14M "Malyutka-M" missiles launched from the BMP-1 were to be guided by the gunner using the same three-point method as the missile operators of any other MCLOS missile system. The three-point method includes three reference points, which are the operator, the missile, and the target. The operator tracks the missile and target and attempts to guide the missile into the target while ensuring that the missile never touches the ground, as opposed to a typical SACLOS system where the operator only has to track the target.
The proper control methods for an MCLOS missile like the 9M14M are detailed in a 1967 Polish article titled "Szkolenie operatorów przeciwpancernych pocisków kierowanych" (Training of anti-tank guided missile operators). The most relevant parts of the article have been extracted below, but the original text can be accessed in this post on the Milimoto blog.
Figure 10a shows the perfect way to control the missile. It is considered as such because it ensures that the missile never comes in contact with the ground or any bushes or fences on the ground situated between the operator and the intended target. The operator in this case would control the missile at a certain height above ground level and then he would lower it to the line of sight just before it impacts the target. However, this guidance method is not practical for an MCLOS missile as this would require the operator to know the distance between the missile and the target at every point on the flight path, and without a rangefinder on the BMP-1, this was not feasible. Therefore, this guidance method could not be used. It is worth noting that years later, the T-64B obr. 1976 implemented the highly advanced "Kobra" ATGM system with a SACLOS guidance system that attained this trajectory with the use of a guidance computer and the integrated laser rangefinder in the tank's 1G42 sight.
Figure 10 (b), (c) and (d) show the best ways to guide a missile over various distances. These methods rely on the fact that the missile's flight is gradually lowered to the operator's line of sight with the target at a certain time, just before it impacts the target. From point P2 of the trajectory shown in the drawings above, the projectile is guided by the three-point method (eye-missile-target) in the so-called attack phase where the missile is in the operator's line of sight with the target. When operating a missile in this phase, the operator must focus his attention and steadily steer the missile. The missile is most likely to touch the ground in this phase.
It is understandable that from the point of view of the operator's psychological capabilities, the attack phase should be as short as possible. In addition, it was calculated that the probability of the missile coming into contact with the ground increases with the passage of the projectile's flight time in the operator's line of sight (because it travels at its minimum altitude during this time). Therefore, guidance time using the three points method at different shooting distances will be different, which will involve the operator having to perform appropriate tracking and flight time assessment activities.
While observing the firing of an ATGM, there were many cases where operators found a lack of psychological resistance under the influence of emotional tension in guiding the missile while it was approaching the target. Some, under the influence of mental illusions, sought to bring the missile to the line of sight as soon as possible (eye-missile-target). In addition, the operator's high emotional tension led to the fact that such shooting usually ended with a missile hitting the ground. Operators who learned the technique of controlling an ATGM and adhered to the rules of approaching the target during the specified time and at the appropriate height, were able to properly stabilize the missile and smoothly enter the attack phase.
When engaging a target situated at a distance of more than 500 meters up to 1,000 meters, the gunner can guide the missile using only his forward-facing TNPO-170A general vision periscope. When the target is further than a kilometer away, it is much more practical to switch to the primary sight as there is much more time for the missile to be captured within the field of view of the gunner. The gunner determines which method to use by first estimating the range to the target using the stadia rangefinder incorporated in his 1PN22M1 sight.
The 6x magnification and the field of view of 15 degrees of the 1PN22M1 sights in the BMP-1 was more than enough to find and engage targets at the maximum aiming range of 1,300 meters of the PG-9 grenade, and based on Soviet requirements, it was also sufficient for finding and engaging targets at 3,000 meters. According to Soviet data, an optical sight with no magnification would allow the gunner to see and identify a tank from a distance of 1.0-1.5 kilometers, while an optical sight with 5x magnification would allow a gunner to do so from 3.0 kilometers. Other data indicates that an optical sight with a magnification of 7-8x would allow a tank to be identified from a distance of 4.0-5.0 kilometers. As such, the magnification of the 1PN22M1 can be considered sufficient for a BMP-1 gunner to fully exploit the maximum range of the 9M14M missile against tanks and other targets of a similar size.
Nevertheless, it should be noted that a higher magnification would be preferable due to the demanding nature of the MCLOS missile guidance principle. Besides the obvious advantage of being able to identify a camouflaged tank at long range more easily with a higher magnification sight, a more enlarged view of the target and the missile would also allow the gunner to steer the missile more precisely. In this regard, the 9K11 man-packed missile complex had an advantage due to the 8x magnification of its 9Sh16 periscopic sight.
It should be noted that because the missile is launched from a rail on top of the gun barrel of the 2A28 "Grom", it will be clear of any obstacles as long as the gunner has a clear line of sight to the target from his primary sight. The gunner can verify this using his general vision periscopes. Moreover, because the missile is launched at a slight elevation angle such that it gains altitude immediately upon leaving the launch rail, it is guaranteed that there will be enough ground clearance to ensure that the stabilizer fins do not touch the ground.
With the gunner's periscopic primary sight and his forward-facing general vision periscopes all on the turret roof and the missile itself being above it, it is possible for a BMP-1 gunner to launch and guide his missiles from a turret defilade position. This is a capability that the BMP-1 shares with missile tank destroyers like the 9P110.
Due to the elevated launch angle built into the 9M14 and 9M14M missile launch system, the initial 500 meters traveled by the missile after its launch is a dead zone where it is not yet under the complete control of the operator. It is not impossible to hit a target inside this dead zone, but it is very unlikely in combat conditions and should not be attempted unless it is an emergency situation as it would otherwise be a waste of ammunition. An absolute minimum range is set by the warhead fuze which is only armed after the missile has traveled 70-200 meters. Engaging targets inside the 500-meter practical dead zone of the missile is done using the 73mm 2A28 cannon. Even without the dead zone, it is always favourable for a BMP-1 gunner to engage it with his cannon instead of an MCLOS missile as the reaction time with the cannon tends to be quicker.
It is often stated that the dead zone exists as a consequence of the limitations of the MCLOS guidance principle, but this is not true. The dead zone exists because of a combination of the waiting time for sustainer engine to start, whereby the thrust vectoring control system becomes active, and the time needed by the missile operator to bring the missile down from altitude to a target at ground level. The 9M14P "Malyutka-P" missile with a SACLOS guidance system had a reduced dead zone of 400 meters thanks to the automatic command unit which is able to visually capture the missile and bring it under control more quickly than a human operator, but the dead zone was inherently quite large due to the peculiarities of the launch system. Later SACLOS missiles like the 9M111 "Fagot" and 9M113 "Konkurs" practically removed the dead zone by implementing a different control mechanism along with a gas generator to launch the missiles at a high initial velocity, thus allowing the missiles to be controlled in direct flight towards the target along the line of sight of the command unit optic immediately after launch.
The operational zone of the 9M14M missile launched from a BMP-1 is much narrower than the same missile launched as part of the 9K11 man-portable complex, but only if the turret of the BMP-1 is not turned to expand the size of the firing arc. Without using the rotation of the turret, the firing arc is only 15 degrees. At a range of 3,000 meters, this arc covers a width of almost 800 meters, so it is enough for slower moving targets such as vehicles being driven cross-country. For the 9K11 complex, the operational width is a whopping 2,240 meters, but this is only achieved if the operator swivels his 9Sh16 periscopic sight. In a BMP-1, the 1PN22M1 sight is fixed to the turret in the horizontal plane, but the gunner can rotate the turret incrementally as the target approaches the edge of his field of view in the sight and thus expand the firing arc of his 9M14M missile to track any moving target.
At night, the 9M14M missile is completely ineffective without external factors to assist the gunner since the night vision module of the 1PN22M1 sight only allows tank-type targets to be identified from a maximum distance of 400 meters with starlight alone. This is less than the practical minimum range of the missile. On a moonlit night with clear skies, it may be possible for a skilled gunner to use the missile, but this is circumstantial. It is only possible to use the missile at night with somewhat consistent results by relying on illumination shells and flares fired over enemy positions. If the opportunity presents itself, gunners can guide a missile towards the light emitted by the headlights of enemy vehicles even in complete darkness.
In the snippet below from the September-October 1975 issue of the Army Reserve magazine, it is stated that in a poll of Israeli tank crews after the 1973 Arab-Israeli war showed that it was extremely difficult to detect the launch of a "Malyutka" missile but most tank commanders could at least detect the missile itself as it traveled towards them. The caveat is that the missiles were detected at long range in only a minority of cases, so while it is reasonable for a "Malyutka" operator to expect a missile launched at an enemy tank to be detected most of the time, it is not feasible to expect the majority of the enemy tank crews to detect the missile until it is already too late to perform evasive maneuvers or to fire back at the launch site.
The chances of detecting incoming missiles in a timely manner may be increased if the crews of multiple tanks in a unit focus their attention in the same area, but on the other hand, those chances may plummet if the tank crew is already preoccupied with fighting other enemy forces.
Based on the experiences of U.S troops in Vietnam, it was possible to distract or agitate the operator of a 9K11 complex by having all nearby personnel fire every weapon available in the general direction of the operator. However, it is reasonable to assume that this tactic was only feasible because of the relatively short combat ranges that were supported by the local environment, and even then, it was not a reliable countermeasure by any means. The same tactic would be even less effective against a BMP-1 gunner who is fully enclosed in an armoured vehicle that offers both physical and psychological protection with a combination of its protection from shell fragments and a certain amount of isolation from the noise of the return fire.
The Hungarian Army estimated that on average, the probability of achieving a hit on a static tank target with an MCLOS "Malyutka" missile was only 20% to 25%. Nevertheless, this modest figure already indicates an advantage over the SS.11 missile which had a recorded probability of hit of 10% based on American experiences in Vietnam during the 1972 Easter Offensive against NVA tanks. Steven J. Zaloga writes in a 1994 article published in Jane's Intelligence Review that a "Malyutka" operator needed to have fired about 2,300 simulated missile shots before he could be qualified. The gunner would also apparently need to practice at the simulator 50 to 60 times a week to maintain that proficiency standard.
Due to the extremely large number of shots needed to train a missile operator to proficiency, the only practical option was to rely heavily on simulators with live fire training sessions occupying a much smaller share of the training regime. Nevertheless, the "Malyutka" series of missiles had an inherent advantage over earlier MCLOS missiles that were steered with spoilers like the 3M6 "Shmel" or the SS.10 instead of a thrust vectoring control system in that the missile was more responsive to the operator's commands. This reduced the chances of the operator accidentally steering the missile into the ground when attempting to guide it onto the target, especially if the target is a tank in a hull defilade position. Needless to say, this was beneficial due to the challenging nature of guiding this type of ATGM, and the relatively high flight velocity of the 9M14M had a generally positive influence on its hit probability as there was less time for the target to evade it.
The relatively light weight of the 9M14M missile and its small dimensions lent itself quite well to relatively quick and easy loading from within the confines of the turret. Arguably easier even in comparison to later IFV designs like the Bradley which forced a passenger to load TOW missiles weighing in excess of 21 kg from the passenger compartment through a large roof hatch. The Bradley could not reload its missiles at all either if no passengers were around to help. For what it's worth, that is a praiseworthy feature of the BMP-1.
To load a missile, the gunner must elevate the cannon to its limit of +30 degrees, open a small hatch in the turret roof directly above the cannon breech, and then slide the missile with its launch rail onto the launcher. To align the missile launch rail with the launcher, the gunner aligns it on top of a pair of rollers on top of the "Grom" cannon breech before pushing the entire assembly forward.
When the launch rail is pushed forward far enough, it is automatically locked in place. The missile has its stabilizer fins folded for stowage and to fit through the small hatch in the turret roof, so the next step for the gunner is to unfold the fins. The gunner could do this by reaching his arm out of the loading hatch, but to minimize his exposure outside of the armoured turret, he was provided with a special stick.
A standard combat load for a BMP-1 includes four 9M14M missiles, of which two are stowed in a ready rack on the turret floor while the remaining two are stowed next to the turret in the passenger compartment. The ready racks are shown in the photo on the left below, and the location of both the ready and reserve racks in the vehicle from a top-down perspective with an arrow to indicate the front of the hull. While in a 9K11 man-portable system, the warhead of the missile would be detached and stowed separately, and then assembled during setup, but for the BMP-1, the missiles are stowed in their assembled form and require only the wings to be deployed.
The ready racks are in a convenient location for the gunner to rapidly reload the launcher without leaving his seat.
In case of an unexpected sudden contact with enemy forces while a BMP-1 unit is on a march, the gunner cannot react immediately as he must first complete a number of preparations. According to Sergey Suvorov in his book "Боевые машины пехоты БМП-1, БМП-2 и БМП-3. «Братская могила пехоты» или супероружие" (BMP-1, BMP-2 and BMP-3 infantry fighting vehicles. "Mass grave of infantry" or a superweapon), no more than 50 seconds is needed to complete the full preparation process to launch a missile. This process not only includes the loading of the missile itself, but also the setup of the guidance equipment.
Officially, the crew standards for a BMP-1 gunner mandate that the ATGM must be readied and fired within 55 seconds for him to pass with a "satisfactory" mark. To pass with a "good" mark, the procedure must be done within 45 seconds, and to pass with an "excellent" mark, no more than 40 seconds must be taken. The procedure is not equivalent to the loading time of a single 9M14M missile as it also involves the readying of the ATGM control system and other tasks. It is described as follows:
To complete the process in reverse, the time taken for a BMP-1 trainee gunner to achieve a "satisfactory" mark is 35 seconds. A time of 30 seconds is required for a "good" mark is 30 seconds, and a time of 25 seconds is required for an "excellent" mark.
Given the preparation times stated in the official standards for trainee gunners, the 50-second time stated by Suvorov is reasonable. In battle, 50 seconds is a very long time and it is only acceptable if there is a long standoff distance between the BMP and the enemy. At long range, the seriousness of the issue is ameliorated to a large extent by the low probability of a direct hit from enemy fire, which is aided by the small silhouette of the BMP-1 itself. At short ranges such as in an ambush scenario, the gunner can react quickly by returning fire with the 2A28 cannon and there is no need to bring the missile into action, but if the target is beyond the effective range of the 2A28 cannon while still remaining close enough to be able to fire upon the BMP-1 with a high probability of hit, then the crew has no options but to have the driver maneuver the vehicle into a covered position.
If the presence of the enemy is known or if enemy contact is determined to be probable, the long-range firepower of the BMP-1 can be maximized by having a missile loaded onto the launch rail from the reserve stowage racks, thus keeping the ready racks full. Ideally, the missiles are used with a considerable standoff distance between the BMP-1 and the target to ensure the greatest probability of survival for the operator. According to safety protocols, it is generally not permitted to keep a missile loaded on the launcher rail during long marches for fear that it may be damaged, as the missile is completely unprotected. In field conditions, a missile is kept loaded on the launcher so that it can be used immediately when it is needed.
If a missile is not already loaded, the maximum rate of fire for the "Malyutka" missiles is two launches in the first two minutes when firing at the maximum range of 3,000 meters, with the first minute being largely taken up by the preparation process (40-55 seconds). After the second round is fired, the gunner must load the launcher with missiles from the reserve racks which can only be done if the turret is turned to the left or to the rear. As such, the combat rate of fire in a non-ideal situation would be less than one launch per minute. If a missile is already loaded, the gunner may be able to launch three missiles in two minutes. All four missiles may be launched in three minutes. The combat rate of fire would therefore be just over one launch per minute. At shorter distances, the flight time of the missile is correspondingly shorter so a somewhat higher overall rate of fire can be expected.
This rate of fire is nominally less than that of the 9K11 man-portable ATGM complex which can achieve a rate of fire of two rounds per minute when firing at the maximum range of 3,000 meters by having an array of prepared missiles launched consecutively, but on the other hand, the 9K11 complex requires a much longer preparation time as the ATGM team must set up multiple missiles on their individual launchers and then link them to a control unit. Case in point, a 9K11 manual states that for a three-man team with two missiles and one control unit, deploying the missile complex takes 1 minute 40 seconds. A much more unfavourable comparison would be between the BMP-1 and a self-propelled missile tank destroyer like the 9P110 which requires practically no setup time and can launch six missiles consecutively. The BMP-1 has a much slower combat rate of fire by comparison.
When resupplying the BMP-1, the missile ready racks are replenished with fresh missiles passed into the turret through the gunner's hatch.
The BMP-1 was never issued with the original 9M14 model. The improved 9M14M model was the basic variant for the BMP-1. All Malyutka-type missiles are compatible with the BMP-1's launcher system.
The Object 765 sp.4, better known as the BMP-1P, had its "Malyutka" missile system replaced with an externally mounted 9P135M launcher post. The joystick control box and the missile launch rail for the "Malyutka" system were removed in this modification. Older BMP models updated to the BMP-1P standard had the missile loading hatch welded in place as shown in the photo on the left below (photo by Yuri Pivkin), while new production turrets did not have a hatch fitted at all, instead having a modified roof construction as shown in the photo on the right below (photo from the militaertechnik-der-nva website).
The situation with the BMP-1P is not so different than its contemporaries like the Marder 1. The Marder 1 did not even have an ATGM launching capability until it was modernized in 1977, and the upgrade only involved installing a simple launcher post beside the commander's hatch, identical in form and function to the one on the BMP-1P. Also, it should also be pointed out that only one Marder in a platoon of three vehicles was given this modification with a MILAN launching unit and the missiles to use with it. This was purely for doctrinal reasons. The Marder's turret has a two-man crew and it is the commander who operates the ATGM, so the gunner is ostensibly free to carry out other tasks unlike in a BMP-1P, but technical limitations limit the gunner of a Marder in his abilities to contribute. While the commander is operating the ATGM system, the turret is locked in place and the autocannon is disabled. The AMX-10P faces a similar conundrum. Clearly, the simplistic implementation of anti-tank missiles on most of the modern IFVs of the time was a global trend that the BMP-1P simply followed. It is no better or worse than its contemporaries in this regard.
It is also worth noting that as a general rule, low-pressure cannons are completely ineffective against low-flying aircraft, including helicopters, if they only fire conventional ammunition with conventional fuzing systems. However, this was largely ameliorated by the inclusion of the 9K32 "Strela-2" MANPADS system with two 9M32 missiles in the combat load of a standard BMP-1 for one of the passengers to use from one of the roof hatches of the passenger compartment or while dismounted. This system entered service in 1968 and was issued to BMP. In 1970, the 9K32M "Strela-2M" system entered service. It had improved performance characteristics compared to its predecessor and featured the ability to engage jet aircraft in a head-on attack, whereas the "Strela-2" was limited to tail chase attacks only. Newer systems such as the 9K34 "Strela-3" began to be issued in the mid to late 1970's, while the 9K310 "Igla-1" and 9K38 "Igla" became available in the early 1980's.
Officially, the 9K32 "Strela-2" was specified for the BMP-1 (Object 765 sp.2), while the 9K32 "Strela-2M" was specified for the BMP-1P (Object 765 sp.4). Only the BMP-2 was officially specified to have the 9K34 "Strela-3" system. However, due to the fact that the MANPADS issued to the vehicles are self-contained systems that are used by the passengers, there was no strict policy on their distribution other than the priority of the motorized infantry units. In practice, even the oldest BMP variants could enjoy the enhanced air defence capabilities provided by the latest MANPADS models if sufficient quantities were issued to replace older models. For example, the photo below shows an "Igla" being used by a passenger in a basic BMP-1. This would be an impossible combination if the specifications were strictly followed.
Two 9M32 or 9M32M missiles with a single launcher could be carried in each BMP. One missile was stowed on top of the central fuel tank with clips while the other missile was stowed on the left hull wall with clips. If the space on top of the central fuel tank was not used for a missile, it could be used to stow an additional RPG-7 grenade launcher. The location of the two missiles is shown in the drawing below. They are marked in red and labeled (15) and (20).
In the book "Soviet/Russian Armor and Artillery Design Practices: 1945-1995" by the Marine Corps Intelligence Activity and in the book "BMP Infantry Fighting Vehicle 1967–94" by Steven J. Zaloga, it is reported that initially, one missile and one launch unit was issued per two vehicles. The exact timeframe was not specified. Later, each vehicle was issued with one launch unit and two missiles, thus quadrupling the number of missiles available in each BMP-equipped motorized infantry unit. With such a high concentration of anti-aircraft weapons, the ability of each unit to defend itself from air attack is highly noteworthy. This was a valuable capability for the Soviet Army given that the Soviet Air Force was not expected to be capable of maintaining air superiority except in some localized areas.
Despite its inherent limitations, this type of air defense system could be considered to be a more effective alternative to the rapid-fire autocannons of foreign IFVs against both modern jet-propelled aircraft and helicopters. Against fixed wing jet aircraft, the probability of kill depends on a number of factors including the number of engines; twin-engine aircraft have a high chance of surviving a hit from a MANPADS missile as it would most likely hit one of its engines, leaving the other engine intact. The overall probability of kill against a jet fighter with the "Strela-2" is stated to be 19-25% in the article "Переносный Зенитные Ракетные Комплексы "Стрела-2" и "Стрела-3"" (Man-portable Air Defense Missile Systems) published in the May 1999 issue of the "Техника и вооружение" magazine. The probability of kill of the "Strela-2M" against the same target was 22-25%, and for the "Strela-3" it was 31-33%. The all-new "Igla" series had greatly enhanced performance, with the "Igla-1" achieving a probability of kill of 44-59% against a jet fighter while the "Igla" could achieve a probability of kill of 45-63% against the same target. These figures are repeated in the book "Зенитные ракетные комплексы" (Anti-Aircraft Missile Complexes) by Nikolai Vasilii and Aleksandr Gurinovich.
Given that two missiles were carried in each BMP, there can be two attempts with an overall probability of hit of 19-25% each, so the theoretical probability of achieving one aircraft kill per BMP using the "Strela-2" can be considered to be 34.9-39.2%, and if the "Strela-3" system was used instead, the probability of one aircraft kill per BMP increases to 52.4-55.1%. Using the newer "Igla-1", the probability of one kill with two missiles increases to 68.6-83.2%. With the much more modern "Igla" the probability of one kill with two missiles increases to 70-86.3%, and indeed, the likelihood of downing one aircraft with a single "Igla" missile is already high enough that two attempts may not be needed.
To achieve a similar probability of hit with a 20mm autocannon aimed with conventional optical sights, hundreds or even thousands of rounds would be required. Indeed, the primary incentive of developing man-portable air defense missile systems during the 1950's and 1960's was the very low efficiency of conventional guns against jet aircraft which were too fast for a human gunner to engage without computer assistance. For example, on page 20 of the book "Self-Propelled Anti-Aircraft Guns of the Soviet Union" by Mike Guardia, it is stated that a M163 VADS firing a 60-round burst at a MiG-21 in level flight from a range of 1 km with its 20mm M61 Vulcan cannon had a kill-per-burst probability of just 0.08, or 8%. To achieve a probability of kill matching the "Strela-2", six 60-round bursts would be required, expending a total of 360 rounds. To achieve a probability of kill matching the "Strela-3", ten 60-round bursts would be required, expending a total of 600 rounds.
It is important to note that the M163 VADS fire control system included a radar rangefinder and an automatic target lead computer, and the M61 Vulcan cannon installed in the M163 had a high rate of fire of 3,000 rounds per minute. To put this in perspective, a Marder 1 IFV had a 20mm MK.20 Rh 202 autocannon that fired at less than a third of the rate of the M61 Vulcan on the M163. The Marder 1 itself had no optical or laser rangefinder, no firing solution calculator, and it had only simple lead markings in its optical anti-aircraft sight. It was the same for the AMX-10P. These IFVs would probably have to expend their entire ready supply of 20mm ammunition simply to guarantee at least one hit on a fixed-wing aircraft, and to achieve a 50% kill probability may require the expenditure of their entire ammunition supply.
Moreover, the maximum range of the "Strela-2" was 3.4 km and its maximum altitude was 1.5 km while the "Strela-2M" had an even longer range of 4.3 km and higher maximum altitude of 2.3 km, which is more than double the maximum effective range and altitude of the 20mm MK.20 Rh202 and HS.820 autocannons against air targets. The larger 25mm M242 chain gun of the M2 Bradley had a longer range than these 20mm autocannons, but it was considered to be only suitable for suppressive fire against helicopters at a maximum range of 2,500 meters while FM 3-22.1 (Bradley gunnery field manual) states that too many rounds are required to achieve a kill when firing at air targets beyond 1,700 meters. The 30mm RARDEN autocannon of the FV510 Warrior had a longer range, but the FV510 itself was wholly inadequate against aircraft of all types due to a combination of the extremely low rate of fire of the RARDEN and the severely limited speed of its hand-cranked gun laying system.
The sole advantage held by IFVs with fast-firing 20mm autocannons is their ability to react more quickly to the sudden appearance of enemy aircraft flying at a low altitude. These may be fixed wing aircraft or helicopter gunships. Fighter-bombers attacking with bombs are a viable target, but ground attack aircraft flying missions against armoured vehicles were almost always armed with rockets. Helicopter gunships were universally armed with rockets for such missions, occasionally supplemented with ATGM systems. Unguided rocket systems like the Hydra 70 and S-8 were typically used from a range of up to 2.0 kilometers against point targets and airborne ATGM systems generally had a range of 3.0 kilometers or longer. With a maximum effective range of 1.5 km against aircraft, 20mm autocannons do not offer any standoff distance against such threats.
The ideal air defence system is a combination of a fast-firing autocannon of a larger caliber with a MANPAD system operated by a passenger - this was later achieved with the BMP-2 which featured a 30mm autocannon with a range of 3.0 km against air targets and a 9K34 "Strela-3" system with a range of 4.1 km or a 9K310 "Igla-1" system with a range of 5.2 km. Such a combination allows two targets to be engaged simultaneously, or for one target to be engaged by both types of weapons for a higher probability of kill.
All in all, it can be said that the BMP was not inferior to later foreign IFVs with 20mm autocannons like the AMX-10P and Marder 1, and it could even be considered to be outright superior to much newer IFVs like the M2 Bradley and FV510 Warrior. Only the BMP-2 surpassed the BMP-1 in this regard.
Besides engaging aircraft with a MANPADS system, it was also possible for the passengers to fire their small arms from the roof hatches at aircraft flying overhead. It would not have been effective, of course, but it was the only option for the passengers of a BMP that was not issued with a MANPADS system.
The 902V "Tucha" smokescreening system was a standard feature of the BMP-1P (Object 765 sp.4) and was retrofitted to older BMP models at an unknown rate. Although it appears to be a straightforward modification, the addition of the "Tucha" system involves more work than the installation of the external missile launcher on the BMP-1P since the grenade launching system connects to the vehicle's electrical system and has its own control box. This means that the old master control panel used to power up ancillary systems had to be replaced with an updated one.
A bank of six 81mm smoke grenade launchers are arranged around the rear of the turret, aimed directly forward. The gunner aimed the grenades using the 1PN22M1 or 1PN22M2 sight. The grenades had to be aimed because they do not produce instantaneous smokescreens for self-concealment but are instead propelled to a range of 200 to 350 meters after launch and emit smoke after landing.
A more detailed examination of 3D6 and 3D17 smoke grenades is available in this page. During the career of the BMP-1 in the Soviet Army, the 3D6 was the only smoke grenade type issued.
Each passenger was provided an internal space of 0.54 cubic meters. The seating positions of the passengers were designed to accommodate average Soviet adult men of a fighting age, but the percentile requirement for the passengers is not known. In terms of real volume, the BMP-1 was marginally superior to the M113 which provided each of its passengers with an internal space of 0.51 cubic meters. However, the relative volume of the BMP-1 was greater than the real volume suggests due to the considerable anthropomorphic differences between Soviet and American men in the 1960's.
To fully appreciate this difference, it is necessary to understand that the 95th percentile American ground forces serviceman had a weight of 91.5 kg based on measurements in 1966 and in 1977 with large sample sizes of USMC and U.S Army personnel, whereas the 95th percentile Soviet young adult male (conscription age) had a weight of 81.57 kg according to the USSR Anthropometric Atlas, 1977. Moreover, Soviet young adult males who reach conscription age in the 1960's should be significantly lighter than their juniors in 1977 due to food shortages during their childhood in the 1940's. Naturally, the dimensions of Soviet men were also smaller than their American counterparts including in critical points such as stature, shoulder width, and leg length, all of which are used as guidelines when allocating space for the passengers in a vehicle.
The significantly smaller bulk and dimensions of young adult Soviet males during the 1960's made the modest internal space of the BMP-1 more comfortable for its passengers relative to the M113, although it was still not luxurious by any standard.
In the U.S, tests of a captured Syrian BMP-1 trophy from the 1973 Yom Kippur war found that the ergonomics of the passenger compartment met the minimum human engineering standards used by the U.S Army. The BMP-1 was deemed to be acceptable for accommodating only 30th percentile American men, whereas the M2 Bradley was designed to accommodate 95th percentile soldiers under the same standards, using ANSUR (U.S. Army Anthropometric Survey) data from the 1970's. Height was given the most attention in the passenger compartment design, but the seating space was still extremely tight in terms of length and width, especially if the passengers wore their standard PASGT gear.
The recoil mechanism consists of a hydraulic recoil buffer and coil return spring. It is wrapped around the base of the barrel and encased in an armoured sleeve, so it is concentric to the bore axis of the cannon. This is a positive influence on the dispersion characteristics of the cannon. Owing to its low operating pressure and its compact overall design, the "Grom" has a recoil stroke of only 150mm.
As the drawing below shows, the trunnion and barrel chamber of the "Grom" are at the same location, and because the BMP-1 turret has a protruding gun mount with the trunnion located in front of the turret ring, the cannon only protrudes a short distance into the turret and only the breech can be seen from inside the turret.
The recoil buffer sleeve also has built-in provisions for mounting the "Malyutka" launching rail. When a missile is mounted on the launcher, the cannon becomes somewhat unbalanced by the weight. The missile itself weighs 10.9 kg and it is located forward of the gun trunnion, making the gun rather front-heavy.
Even back in 1966, it was a somewhat unusual decision to use a low-velocity cannon in lieu of the typical heavy machine gun or autocannon as was normal for both purpose-built IFVs as well as APCs pressed into service in the IFV role. The convention that was followed by foreign militaries at the time was based on relatively sound reasoning: in a typical skirmish where tanks do not need to be involved, an armoured troop carrier should only face light resistance, and indeed, the ACAV modification of the M113 that was used by U.S forces and the ARVN during the war in Vietnam was only armed with externally-mounted M2 and M60 machine guns with gun shields for protection, and this was deemed to be enough for shock action against light infantry. In most cases, even a basic M113 was effective when the opposition was armed only with small arms and small numbers of anti-tank weapons. If additional firepower is desired for a vehicle intended for the same role, a rapid-fire autocannon would be more efficient at dispatching infantry, soft-skinned targets and lightly armoured vehicles compared to a large caliber semi-automatic cannon, but a rapid-fire autocannon has a lower efficiency against dugouts and field fortifications.
From this, it is evident that the BMP-1 was largely incapable of countering man-portable ATGMs which is a noteworthy drawback as the BMP-1 entered service during an era when such weapons were prolific. The effectiveness of the "Grom" in this role was increased when OG-15V HE rounds were introduced, but even so, another limitation came in the form of the rather short 1,600-meter maximum range of the OG-15V round.
If the BMP is being used to supplement a breakthrough attempt, it will not be the centerpiece of the attack. Soviet field manuals detail a number of formations to be used against enemy forces in certain situations, and in one of these, it is stated that when tanks are available to support the advance, one tank can be attached to each motorized infantry platoon. The three BMPs of the platoon follow the tank at a distance of 100 to 200 meters, with either dismounted or mounted infantry. The tank will take care of the toughest targets with its cannon, and the BMPs will knock out anti-tank weapons and lightly armoured vehicles in support of the tank. When a motorized infantry platoon with BMPs is operating without tank support, the modest capabilities of "Grom" would be the most potent anti-armour weapon available to the platoon besides the integrated "Malyutka" missile, so avoiding contact with enemy tanks is a priority. If enemy tanks are not encountered, the 73mm cannon will prove most useful against hardened field fortifications, buildings, and fixed weapon emplacements like machine gun and recoilless rifle nests, and so on. The penetration and blast effect of its HEAT grenades would be particularly useful on fortifications that are otherwise completely immune to machine gun fire, like a triple layer of sandbags (a common standard during the Vietnam war) or a double layer of sandbags reinforced with timber.
Given that the light weight of the BMP-1 allows it to be deployed where tanks cannot go, the firepower of a 73mm cannon becomes particularly meaningful for the troops that are deployed together with the vehicle. From this perspective, there were clear merits to the use of the 73mm "Grom" in the BMP-1. Indeed, there are are a multitude of valid reasons why a weapon like "Grom" is preferable for the BMP rather than a heavy machine gun or a rapid fire autocannon. For one, the firepower of a large caliber cannon is indispensable in many situations. The need for such weapons was met in Vietnam by configuring the M113A1 ACAV with a pintle-mounted 106mm M40A1 recoilless rifle to be operated from the passenger compartment roof hatch. The M113 ACAV with the M40A1 had tremendous firepower but the vehicle provided no protection whatsoever for the gunner and had a severely constrained rate of fire due to the small roof hatch of the passenger compartment and inconvenient location of the weapon itself; the rear of the gun tube extended behind the roof hatch, so the loader has to contort himself to fit each cartridge - almost a meter long and weighing 16.4 kg - through the breech. It was also unsafe for personnel to stand behind or even near the vehicle when the M40A1 is in use due to the colossal back blast and firing signature. The British FV432 "WOMBAT" had an even more powerful 120mm L6 "WOMBAT" recoilless rifle mounted in a layout similar to the M113 and thus shared the same fundamental shortfalls, exacerbated by the more massive size (more than 1.1 meters) and weight (27.2 kg) of the cartridges. As such, these vehicles were tactically distinct from the BMP-1 and neither of the two were proper analogues.
The British Alvis Saladin armoured car and FV101 Scorpion reconnaissance vehicle were both armed with 76mm low pressure guns in fully enclosed turrets, and the Australian Army developed a closer analogue of the BMP-1 in 1967 by mating the fully enclosed turret of the Saladin armoured car with a 76mm L5A1 low pressure gun to the hull of the M113A1, thus creating the Saladin FSV (Fire Support Vehicle). The Saladin FSV is shown in the photo belo. In continuation of this concept, the MSV was created in 1976 by mating the turret of a Scorpion with its 76mm L23 low pressure gun to the M113A1. But even so, these were still fire support vehicles and not pure IFVs. The BMP-1 was completely unique in its combination of traits in 1966 and for better or worse, remained unique throughout the remainder of the Cold War.
From the perspective of the Bundeswehr, the decision to mount the 20mm HS.820 on the SPz 12-3 and the 20mm Rh202 on the Marder was motivated by the need for sufficient firepower to deal with dismounted infantry and lightly armoured troop carriers. In the Soviet Army, this need was met by using a combination of a 14.5mm KPVT heavy machine gun and a 7.62mm SGMT or PKT general purpose machine gun. This armament scheme was established as the standard armament of Soviet armoured personnel carriers and armoured cars beginning with the BRDM-2 (1962) and the BTR-60PB (1966) which both used the same BPU-1 turret. The KPVT would be used against armoured personnel carriers - such vehicles would typically only have limited protection from 12.7mm machine guns - and infantry behind solid obstacles, and the SGMT or PKT would be used against infantry in the open. Although the KPVT was not as useful in the anti-personnel role as a 20mm or 23mm rapid-fire autocannon as its caliber is too small to deliver an effective explosive payload, it fulfilled the same niche in every other respect and was more than adequate for armoured personnel carriers. With this in mind, an escalation in firepower to encompass tanks as the primary target for an IFV like the BMP-1 is not unusual.
ACCURACY
According to the firing table for the PG-9 grenade fired from the 2A28 cannon, the technical dispersion of the PG-9 grenade is 0.6 mils in both the horizontal and vertical axes. The technical dispersion of the OG-9 grenade fired from the 2A28 is 0.9 mils in the horizontal axis and 1.0 mil in the vertical axis.
The point blank range of the cannon with PG-9 HEAT grenades against a medium tank target with a height of 2.7 meters is 800 meters. Theoretically, this allows the gunner to neglect the range estimation process and open fire immediately at a tank within 800 meters with a reasonable expectation of scoring a first-round hit, but due to the dispersion of each shot, the reality is that range estimation is still required to achieve a reasonable probability of hit.
According to comparative data published in the book "БМП-1 (1964-2000): Боевая машина пехоты" by Sergey Malyshev, a basic BMP-1 only has a 35% chance of eliminating an ATGM team with two shots from its cannon at a range of 500 meters. This drops to a measly 10% at a range of 1,000 meters. For comparison, a 30mm autocannon (the 2A72 in this case) has a 100% chance of eliminating an ATGM team with sixteen shots at 500 meters, 50% chance at 2,500 meters, and 40% chance at a range of 4,000 meters. In this comparison, both vehicles are stationary. Against ground targets, the main downside of the 73mm HEAT rounds fired from the "Grom" is that they have an extremely limited fragmentation effect and the explosive charge is not powerful enough to ensure the elimination of soft-skinned targets in the open unless it detonates close to the target.
According to the same book, the probability of destroying an armoured personnel carrier with two shots from the 2A28 cannon is 80% at a range of 500 meters. This drops to only 25% at a range of 1,000 meters. Keep in mind that the probability of destruction is not the same as the probability of hit, as each hit is not guaranteed to destroy the target.
Zaloga claims that the "Grom" can achieve a 70% hit rate on a stationary tank-type target at 500 meters in still air, degrading to 50% at 800 meters. This is not high compared to a high velocity tank cannon, but still quite respectable, as this is already somewhat close to the performance level of the T-62 firing 3UBK-3 115mm HEAT shells, as you can see in the TRADOC bulletin diagram below. An M60A1 could achieve an 80% hit rate with its own 105mm HEAT shells at the same range thanks to its optical coincidence rangefinder.
Without knowing the target that was used to determine the probability of hit data supplied by Zaloga, it is not possible to make any firm conclusions. Nevertheless, the ineffectiveness of the "Grom" cannon at long range is hardly a secret, and its maximum effective range of 800 meters may not even be achievable in practice. During one a live firing trial, a BMP-1 was made to open fire against a stationary T-55 tank at 800 meters. Out of 50 shots, only 17 hit the tank; the others were carried off their trajectory by the wind. This translates to a 34% hit rate.
Nevertheless, it is worth pointing out that a T-55 is smaller than a typical NATO tank. The British Chieftain tank, for example, is 2.9 meters tall and 3.66 meters wide. The American M60A1 has a similar height of 2.9 meters (not counting the very large commander's cupola) and 3.63 meters wide. The German Leopard 1 was 2.6 meters tall and 3.25 meters wide while the French AMX-30 was by far the smallest at 2.52 meters in height and only 3.1 meters in width. The T-54 is only 2.4 m tall and 3.37 m wide. The probability of hit will be higher at all ranges against a larger target, and vice versa. Therefore, it can be inferred that the "Grom" has a slightly higher than 50% chance of hitting a stationary M60 or Chieftain at a distance of 800 meters under favourable weather conditions when using the standard PG-15V HEAT round. The gunner will have to rely more on the ATGM when engaging tanks at distances exceeding 800 meters, and will become totally dependent on the ATGM when fighting at distances of more than 1,300 meters.
As a fighting system, the "Grom" cannon was the most potent direct fire weapon organic to a motorized infantry squad equipped with a BMP-1. An RPG-7 with five grenades would be carried by the grenadier in the squad and it would be operated together with the assistant grenadier. The RPG-7 was a powerful weapon in its own right, but it belonged to a different class than that of the "Grom". The penetration power of the original 85mm PG-7V grenade from 1961 was also less compared to the 73mm PG-9 fired by the "Grom" - 260mm RHA compared to 300mm RHA. In 1969, the improved 70mm PG-7VM grenade entered service with a warhead derived from the PG-9 and a modified propulsion system. The deflection of the projectile from crosswinds was decreased by 1.5 times and the accuracy of fire was increased by around 20-25%. But even with these improvements, the probability of hitting targets beyond 300 meters was still a challenge.
A further examination of the functional precision of the PG-7V rocket grenade when fired from an RPG-7 against tank targets can be found in "Analysis of Rocket-Assisted Aspects of Infantry Antitank Weapons" by Dr. Thomas H. Dawson published in the November-December 1975 issue of the Army Research and Development News Magazine. The article details the technical aspects of the PG-7V rocket itself and considers its advantages and disadvantages, concluding that the drawback of increased wind deflection of the rocket design is completely overshadowed by the greatly reduced margin of error allowed in range estimations due to the increased velocity. It was found that compared to a conventional projectile with a muzzle velocity of 100 m/s, a rocket-assisted grenade like PG-7V with a boosted velocity of 300 m/s decreases the angular elevation (range estimate) error by a factor of more than 10, while the angular deflection (crosswind) error increases only by 3 times.
The hit probability data presented in the graph below shows the probability of a PG-7V grenade achieving a first round hit on a 2.3 x 2.3 meter square target with the same nominal ranging error of 15% (stadia rangefinder), technical shot dispersion of 2 mils, and the same crosswind of 3 m/s. Compared to a hypothetical conventional grenade with a muzzle velocity of 100 m/s and no rocket booster, the effective range of the PG-7V - defined as the distance at which a 50% hit probability is achieved - is twice that of the conventional grenade. The hit probability of PG-7V reaches 80% at a range of 140 meters, and it is 20% at 300 meters.
This shows that in a worst-case scenario where a crosswind is present, the effective range of the rocket-assisted grenade is 2 times better than the conventional grenade. When a crosswind is not present, the advantage of the rocket-assisted grenade is even larger.
This is corroborated by data on the number of shots needed to "defeat" an armoured target in various situations is detailed in page 58 the manual "Наставление по стрелковому делу Ручной противотанковый гранатомет РПГ-7, РПГ-7Д " (Manual on the Matters of Firing Hand-held Anti-tank Grenade Launcher RPG-7, RPG-7D) from 1972. The manual does not specify the type of armoured target or the definition of "defeat", but it can be reasonably assumed that the figures refer to the number of shots needed to hit a tank rather than the number of shots needed to kill a tank, as multiple direct hits are usually needed to knock out a postwar tank. Three types of targets are specified: a frontal aspect of a target moving at 20 km/h, a profile target moving at 20 km/h, and a target situated in a hull-down position.
At 100 meters, both the original PG-7V round and the improved PG-7VM round needed only one shot on the frontal aspect of a target moving at 20 km/h, one shot is needed on the profile of a target moving at 20 km/h, and one shot is needed for a tank in a prepared hull-down position. When the distance increases to 200 meters, the number of PG-7V rounds needed increases to two for the frontal target and four for the hull-down target, and the higher precision of the PG-7VM round begins to show itself as only three shots are needed for the hull-down target. The gap in accuracy between the PG-7V and the PG-7VM widens as the distance increases, but the limits of the RPG-7 are quite evident as the PG-7VM round achieves a 50% hit probability for the front silhouette and side silhouette of moving tanks at just 200 meters and 300 meters respectively. For comparison, the Carl Gustaf M2 (m/48) achieves the same hit probability against a moving tank at a range of 150 meters.
In a best-case scenario where the target is a static tank and there is no crosswind, the effective range where the RPG-7 achieves a 50% hit probability reaches 250 meters. The Carl Gustaf M2 (m/48) achieves the same hit probability at a range of 200 meters. The difference can be attributed to the difference in the flight velocities of the grenades fired by the two antitank systems. The RPG-7 launches a rocket-assisted grenade at a muzzle velocity of only 140 m/s but the projectile accelerates to a peak velocity of 300 m/s after it leaves the launcher, after which it starts to decelerate. The Carl Gustaf launches its HEAT grenade at a muzzle velocity of 255 m/s and the grenade experiences a continuous deceleration until it reaches the target.
At a range of 250 meters, "Grom" has a 90% chance of hitting a stationary tank-type target with its PG-9V grenade. Compared to the RPG-7 carried and operated by the anti-tank grenadier in the squad transported in a BMP-1, the maximum effective range of the "Grom" against a tank-sized target is up to three times higher. Most of the difference can be attributed to the much higher velocity of the PG-9V grenade: the muzzle velocity of the PG-9V is 400 m/s m/s and the maximum velocity is 665 m/s. In comparison, the PG-7VM round remains subsonic throughout its entire flight. The probability of hit with an RPG-7 was therefore much more sensitive to errors in range estimates and it was additionally affected by operator stance, which is a factor that is not relevant for a tripod-mounted weapon like the SPG-9 or the vehicle-mounted "Grom".
However, the PG-9 grenade had much higher drag than a typical spin-stabilized round fired from a tank gun and was intrinsically limited in its range. Needless to say, "Grom" was far from a match for postwar tank guns and as such, the BMP-1 would be consistently outgunned in any duel with a tank if it relied on its cannon alone. However, the advantage of the BMP-1 against contemporary tanks is that the gunner can fire an ATGM from under armour protection in a turret-down position at ranges where the enemy tank has practically no chance of scoring a direct hit. This is thanks to the combination of a periscopic sight on the turret roof and the mounting of the 9M14 "Malyutka" launch rail on the gun barrel above the level of the turret roof. Even if the BMP is in a hull-down position rather than a turret-down position, the extremely small silhouette of the turret makes it very easy to conceal and very difficult to hit with direct fire at the normal operating ranges of the "Malyutka" missile.
In other words, the short effective range of the "Grom" was not a problem when considering the full suite of weapons on the BMP-1 in its totality.
AUTOLOADER
The cannon is fed with 40 rounds of ammunition by an autoloader mechanism, all of which is stored in a crescent-shaped conveyor. No additional ammunition was carried in reserve stowage racks. The electrically powered autoloader conveyor is designed to ensure a continuous supply of ammunition for the autoloader.
The conveyor is essentially a chain with external spokes where the 73mm rounds are attached. The drive sprocket, shown in the drawing on the left below and in the photo on the right below, is directly behind the gunner's seat. The electric motor for the conveyor is installed in the turret.
To initiate the loading cycle, the gunner presses a switch on his powered gun control handles. Because the autoloader was only capable of loading HEAT rounds, it was not necessary for the conveyor to have any internal memory and it lacked the ability to cycle to an ammunition type of the gunner's choice. The conveyor moves by one step with each loading cycle.
In 1973, a modification to the autoloader was made so that when the gunner pressed the "K" (HEAT) button on his control handles, the conveyor would cycle until the tip of a HEAT grenade touched a microswitch mounted to the turret ring, positioned at the loading axis. This would trigger the conveyor to brake, and for the loading process to begin. If the gunner pressed the "O" (HE-Frag) button on his control handles, the conveyor would simply run for as long as the button was held down, ignoring any HEAT grenades passing by the microswitch. In this way, the gunner could cycle through the conveyor until he has a HE-Frag grenade within reach. He can then proceed to load it manually.
To load, the autoloader arm hinges upwards, and the grenade is pitched forward over the gunner's right shoulder and into the breech. To load, the cannon must be elevated by +3 degrees.
The ammunition conveyor occupies the 1 o'clock to 7 o'clock sector of the perimeter of the turret floor.
The autoloader elevator arm is shown in the two pictures below. The photo on the left by Robert De Craecker shows a BMP-1 formerly belonging to the NVA.
The loading tray is shown in the drawing below in its ramming position.
The time taken to complete a loading cycle is 6 seconds. This figure includes the time taken for the gun to elevate or depress to the proper loading angle and then return to the original elevation angle when gunner pressed the "load" button.
When the autoloader is not used, the loading speed is theoretically the same. Officially, the crew standards for a BMP-1 gunner mandate that the 2A28 gun loaded in 6 seconds for him to pass with a "satisfactory" mark. To pass with a "good" mark, the procedure must be done within 5 seconds, and to pass with an "excellent" mark, no more than 4 seconds must be taken. The loading time was defined as the period starting with the commander issuing the order to load and ending with the gunner announcing that the gun is ready to fire.
The manual states that the gunner should not hold his arm close to or in front of the autoloader as this could cause the autoloader to malfunction, presumably due to his jacket getting pinched by the swinging arm, but it is unlikely for the gunner's arm to be "eaten" for the simple fact that the autoloader arm just isn't powerful enough to tear an arm off. However, if there is any truth to the oft-repeated "fact" that Soviet tank autoloaders created an entire generation of armless tank gunners, it should have spawned from the BMP-1. For some reason, the BMP-1 has never been associated with gunners missing arms, even though it is the only Soviet armoured vehicle with an autoloader where this could technically be possible.
Besides the arm guard installed on the gunner's seat, there is an additional perforated metal shield fixed to the turret to separate the gunner's seat from the autoloader mechanism. It is shown in the drawing below.
The ammunition stowage simply does not meet modern standards of safety, not to mention that the overall design of the BMP-1 itself is now completely outdated, but the level of safety was quite typical for armoured vehicles of the late 1960's and was not unusual by those standards. Any IFV, modern or otherwise, would burn up if its ammunition were directly struck by an anti-tank weapon. It is worth noting that because the BMP-1 has all of its ammunition in the hull below the turret ring, there is no ammunition in the turret so that a hit to the turret has a minimal chance of causing a catastrophic kill.
Like the BMP, the AMX-10P carries 325 rounds of ready 20mm ammunition in the fighting compartment below the turret ring in addition to another 475 rounds of reserve ammunition in the hull. The Marder 1 also carries a total of 1,250 rounds of 20mm ammunition in the turret and hull as well, along with its stock of MILAN missiles. It is no different with the Bradley, as it carries hundreds of 25mm rounds in the turret, a few TOW missiles and a Dragon missile in the passenger compartment. If any of these vehicles were to be hit anywhere across the side of the hull with an RPG grenade, the missiles or ammunition may be hit. In this context, the BMP-1 is not much different from any other design of its time.
Replenishing the autoloader conveyor is done by hand. It takes only a few minutes to stock up a full load of 40 rounds due to the compactness of each 73mm cartridge.
Between 1966 to 1973, the standard combat load for the 73mm 2A28 cannon of the BMP-1 consisted of 40 HEAT rounds. The standard combat load for the BMP-1 beginning in 1974 was 16 HE-Frag rounds and 24 HEAT rounds. As one would expect, the loadout can change depending on the tactical situation.
The only real difference between the ammunition for the "Grom" and the "Kopye" is the means of propulsion - whereas PG-9 rockets were to be fired from an open-ended tube that is the SPG-9 recoilless gun, the PG-15V is fired from a closed-breech gun. As such, PG-15P cased propellant charges were used instead of PG-9P bagged propellant charges. The case is made from galvanized steel. According to the CAT UXO website, the rimmed stub case has a rim diameter of 83mm and a mouth internal diameter of 63mm.
The coupler assembly for both the PG-9P and PG-15P can fit the standard PG-9 grenade and warhead assembly. It is possible for a PG-9V round to be converted to PG-15V rounds by simply swapping out the PG-9P propellant charge for the PG-15P propellant charge. The coupler is designed to ignite the tracer and begin the rocket motor fuze via transferring the primer ignition spark. The EKV-23A primer in the PG-15P charge is an electric-percussion primer. It can be initiated electrically, or mechanically via the striker pin, giving the option to either fire a round normally using the electric trigger on the gunner's control handles, the electric trigger on the manual elevation handwheel, or using the manual lever-operated striker pin incorporated into the breech block of the gun.
The entire PG-15P charge weighs just 0.96 kg in total, but the mass of the propellant is only 0.16 kg. Without needing to vent out most of the expanding hot gasses of the propellant charge out the back of the gun tube like in the SPG-9, it became possible to reduce the amount of propellant while maintaining the same muzzle velocity. The small size of the PG-15P is a crucial benefit in the small one man turret, helping to reduce the total length of the rocket to acceptable limits. Nevertheless, the complete cartridge is still quite long.
As shown in the photo below, the top lid of the charge casing is breached upon firing, but the lid is deformed in such a way that the passage from the casing to the cannon chamber and the barrel is restricted. This reduces the rate of pressure release and thus reduces the chamber pressure by some amount, which translates to a small reduction in the recoil impulse of the cannon.
Since the introduction of the OG-15V in 1973, the PG-15V was relegated to a backup role against non-armoured targets. PG-15V itself was replaced by PG-15VS with a more potent armour piercing effect in the same year.
The PG-15V cartridge combines the PG-9 fin-stabilized rocket grenade assembly used by the SPG-9 with the proprietary PG-15P propellant charge. Introduced in 1962 alongside the SPG-9 as part of the PG-9V round, the PG-9 was originally intended to fulfill the anti-armour role, but it was initially used for anti-personnel purposes as well due to a lack of options at the time.
To load, the autoloader arm hinges upwards, and the grenade is pitched forward over the gunner's right shoulder and into the breech. To load, the cannon must be elevated by +3 degrees.
The ammunition conveyor occupies the 1 o'clock to 7 o'clock sector of the perimeter of the turret floor.
The autoloader elevator arm is shown in the two pictures below. The photo on the left by Robert De Craecker shows a BMP-1 formerly belonging to the NVA.
The loading tray is shown in the drawing below in its ramming position.
The time taken to complete a loading cycle is 6 seconds. This figure includes the time taken for the gun to elevate or depress to the proper loading angle and then return to the original elevation angle when gunner pressed the "load" button.
When the autoloader is not used, the loading speed is theoretically the same. Officially, the crew standards for a BMP-1 gunner mandate that the 2A28 gun loaded in 6 seconds for him to pass with a "satisfactory" mark. To pass with a "good" mark, the procedure must be done within 5 seconds, and to pass with an "excellent" mark, no more than 4 seconds must be taken. The loading time was defined as the period starting with the commander issuing the order to load and ending with the gunner announcing that the gun is ready to fire.
The manual states that the gunner should not hold his arm close to or in front of the autoloader as this could cause the autoloader to malfunction, presumably due to his jacket getting pinched by the swinging arm, but it is unlikely for the gunner's arm to be "eaten" for the simple fact that the autoloader arm just isn't powerful enough to tear an arm off. However, if there is any truth to the oft-repeated "fact" that Soviet tank autoloaders created an entire generation of armless tank gunners, it should have spawned from the BMP-1. For some reason, the BMP-1 has never been associated with gunners missing arms, even though it is the only Soviet armoured vehicle with an autoloader where this could technically be possible.
Besides the arm guard installed on the gunner's seat, there is an additional perforated metal shield fixed to the turret to separate the gunner's seat from the autoloader mechanism. It is shown in the drawing below.
The ammunition stowage simply does not meet modern standards of safety, not to mention that the overall design of the BMP-1 itself is now completely outdated, but the level of safety was quite typical for armoured vehicles of the late 1960's and was not unusual by those standards. Any IFV, modern or otherwise, would burn up if its ammunition were directly struck by an anti-tank weapon. It is worth noting that because the BMP-1 has all of its ammunition in the hull below the turret ring, there is no ammunition in the turret so that a hit to the turret has a minimal chance of causing a catastrophic kill.
Like the BMP, the AMX-10P carries 325 rounds of ready 20mm ammunition in the fighting compartment below the turret ring in addition to another 475 rounds of reserve ammunition in the hull. The Marder 1 also carries a total of 1,250 rounds of 20mm ammunition in the turret and hull as well, along with its stock of MILAN missiles. It is no different with the Bradley, as it carries hundreds of 25mm rounds in the turret, a few TOW missiles and a Dragon missile in the passenger compartment. If any of these vehicles were to be hit anywhere across the side of the hull with an RPG grenade, the missiles or ammunition may be hit. In this context, the BMP-1 is not much different from any other design of its time.
Replenishing the autoloader conveyor is done by hand. It takes only a few minutes to stock up a full load of 40 rounds due to the compactness of each 73mm cartridge.
73MM AMMUNITION
Between 1966 to 1973, the standard combat load for the 73mm 2A28 cannon of the BMP-1 consisted of 40 HEAT rounds. The standard combat load for the BMP-1 beginning in 1974 was 16 HE-Frag rounds and 24 HEAT rounds. As one would expect, the loadout can change depending on the tactical situation.
Propellant Charge
The only real difference between the ammunition for the "Grom" and the "Kopye" is the means of propulsion - whereas PG-9 rockets were to be fired from an open-ended tube that is the SPG-9 recoilless gun, the PG-15V is fired from a closed-breech gun. As such, PG-15P cased propellant charges were used instead of PG-9P bagged propellant charges. The case is made from galvanized steel. According to the CAT UXO website, the rimmed stub case has a rim diameter of 83mm and a mouth internal diameter of 63mm.
PG-15P
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The entire PG-15P charge weighs just 0.96 kg in total, but the mass of the propellant is only 0.16 kg. Without needing to vent out most of the expanding hot gasses of the propellant charge out the back of the gun tube like in the SPG-9, it became possible to reduce the amount of propellant while maintaining the same muzzle velocity. The small size of the PG-15P is a crucial benefit in the small one man turret, helping to reduce the total length of the rocket to acceptable limits. Nevertheless, the complete cartridge is still quite long.
Upon initiating the primer, the ignition charge (3) held in a perforated tube in the center of the charge is set off. This sends a jet of hot gasses into the PG-9 grenade via the coupler assembly, and at the same time, the flame front exits the perforated tube radially and ignites the propellant charge uniformly. The combusting propellant builds up pressure until the top lid of the PG-15P charge, which is made of aluminium, is breached and the gasses are expelled into the gun chamber, where it can begin to set the PG-9 grenade in motion.
As shown in the photo below, the top lid of the charge casing is breached upon firing, but the lid is deformed in such a way that the passage from the casing to the cannon chamber and the barrel is restricted. This reduces the rate of pressure release and thus reduces the chamber pressure by some amount, which translates to a small reduction in the recoil impulse of the cannon.
HEAT
To deal with all ground targets, including both armoured and unarmoured targets, the PG-15V HEAT round with the PG-9 grenade was the only available option to BMP-1 gunners. It had a pure HEAT grenade only meant for armoured targets, having only a negligible fragmentation effect unlike HEDP grenades. Despite its low efficiency against targets other than armoured vehicles, BMP-1 gunners were instructed to use this round against infantry in the open and in fortified positions for lack of a better option until the OG-15V round became available.
Since the introduction of the OG-15V in 1973, the PG-15V was relegated to a backup role against non-armoured targets. PG-15V itself was replaced by PG-15VS with a more potent armour piercing effect in the same year.
PG-15V
The PG-15V cartridge combines the PG-9 fin-stabilized rocket grenade assembly used by the SPG-9 with the proprietary PG-15P propellant charge. Introduced in 1962 alongside the SPG-9 as part of the PG-9V round, the PG-9 was originally intended to fulfill the anti-armour role, but it was initially used for anti-personnel purposes as well due to a lack of options at the time.
The rocket engine is located at the rear of the projectile, in front of the folding stabilizer fins. Rocket propellant is contained inside the cylindrical segment at the middle of the projectile and the exhaust gasses exit from a Venturi nozzle at the rear end of the projectile, unlike an RPG-7 rocket where multiple exhaust nozzles are arranged around the circumference of the rocket just behind the grenade warhead. A raised lip in front of the stabilizer fins acts as a bore obturator.
Due to the low pressure of the PG-15V round and its low muzzle velocity, the acceleration forces during the launch of the PG-9 grenade were relatively tame. This allowed the thickness of the warhead casing to remain thin and thus allow the diameter of the shaped charge to be maximized. However, the grenade could still acquire a relatively high velocity of 665 m/s thanks to its rocket booster. This allowed it to have a point blank range of 765 meters for a target with a height of 2 meters. For comparison, the BR-350B APBC shell fired from the 76.2mm D-56T gun of the PT-76 had a muzzle velocity of 655 m/s and a point blank range of 780 meters against a target with a height of 2 meters, so it had a marginal point blank range advantage of just 15 meters over the PG-15V. This was due to the lower drag forces experienced by the APBC shell compared to the finned PG-9 grenade. However, when comparing the PG-15V to the 76.2mm BK-354(M) HEAT shell which had a muzzle velocity of just 550 m/s and a point blank range of 630 meters for a target that is 2 meters tall, the relationship is reversed and the PG-15V gains a considerable point blank range advantage.
In other words, the use of rocket assistance technology allowed Soviet engineers to create a HEAT grenade that had superior ballistic performance to a 76.2mm HEAT shell fired from medium-pressure gun while having superior armour penetration performance.
The PG-9 warhead has a conical shaped charge liner made from 40Kh low alloy steel which is widely used for structural purposes where increased strength is required. Compared to a shaped charge with a copper liner, the effectiveness of a steel liner in penetrating armour is somewhat lower, but the post-perforation effect tends to be substantially greater owing to the larger diameter of the penetration cavity. According to a drawing from a January 1997 edition of "Projectile and Warhead Identification Guide", the shaped charge cone has a diameter of 61.7mm and an apex angle of 60 degrees. The liner has a variable thickness, from 1.27mm near the rim to 1.02mm at the apex. The warhead has 258mm of built-in standoff distance between the shaped charge and the tip of the fuze. The use of a variable thickness liner and a wave shaper was a highly advanced feature for a 1962 grenade, as most foreign HEAT shells of the time still lacked even a wave shaper.
The casing of the PG-9 grenade is made from aluminium and weighs only 0.9 kg. A light aluminium casing is exceptionally poor at fragmentation compared to the typical steel casings of tank-fired HEAT shells, and indeed, thin aluminium casings are used in offensive hand grenades like the RGN grenade for this reason. The poor fragmentation effect makes the PG-9 highly anemic against dispersed infantry on open ground, but the 0.322 kg explosive charge can still cause significant damage to light fortifications as it is equivalent to a 0.515 kg TNT charge. In practice, the actual blasting effect should be stronger than the explosive weight alone suggests, because according to studies such as "The analysis of the equivalent bare charge of aluminum cased charge exploding in confined space", the reactivity of aluminium casings on TNT charges increases the total energy of the explosion by 18-26%. The combustion of aluminium particles among the other detonation products acts as a fuel additive, increasing the heat of the explosion and thus enhancing the blast loading.
In total, the explosive charge is only slightly weaker than a conventional tank-fired 75mm or 76mm HE shell filled with TNT. Heavy concrete barriers, brick and concrete walls, sandbag walls, timber barriers and other types of field fortifications can be destroyed with confidence. When firing at troops in the open, a BMP-1 gunner will have to rely mainly on his PKT coaxial machine gun, as an HE effect is not efficient in open spaces.
The PG-9V grenade uses the VP-9 piezoelectric point-initiating, base-detonating (PI-BD) fuze. It features an inertial safety mechanism and it has a self-destruct system that automatically detonates the grenade 4-6 seconds after it is armed. The fuze is armed at a distance of 2.5 to 20 meters from the muzzle of the gun by the braking force of the deceleration from air resistance and the deploying stabilizer fins on the grenade. The nose fuze is connected to the base detonator by the aerodynamic fairing connecting the warhead to the fuze, and an internal conductive cone, which links the positive terminal of the element to the negative terminal of the base detonator via the shaped charge cone. On impact with an obstacle, the mechanical stress induced in the piezoelectric element is converted into an electrical current. The current travels down the conductive cone and shaped charge liner, and into the base detonator, setting off the warhead.
The metal safety cap on the VP-9 is designed to protect the piezoelectric element. It mainly serves as an additional drop safety measure as it helps to protect the ceramic piezoelectric element from cracking by rough handling. If the safety cap is left on when the grenade is fired, it prevents the fuze from initiating on heavy rain, twigs, and other minor obstacles. An impact on a hard and unyielding object is necessary to initiate the fuze. This makes the grenade unsuitable for firing targets other than vehicles and structures. If the safety cap is removed, the VP-9 behaves as a highly sensitive superquick fuze. It initiates on any obstacle, and the delay of the fuze is the same as any other domestic piezoelectric fuze of its type - less than 0.0001 seconds, though the specific time is unknown. This makes the grenade suitable for firing at personnel in the open as it ensures the maximum fragmentation effect. For the BMP-1, the grenades are usually loaded into the autoloader with the safety cap on.
In either case, the VP-9 provides instant action even at an impact velocity corresponding to point blank range, thus ensuring that the warhead of the grenade is detonated at the proper standoff distance without any reduction in the standoff distance by the crumpling of the grenade casing.
As with any other thin-skinned grenade, it is possible to defeat the PG-9 using slat armour with gaps of an appropriate size, and certain types of chain link fencing can also have the same effect, though the reliability is significantly diminished. If the grenade flies between two slats with a gap less than 73mm wide, the fuze does not initiate, while the slats short-circuit the fuze by crushing the aerodynamic fairing against the conductive cone, and the destroy the warhead itself by cutting through the shaped charge liner. The probability of success for this type of armour tends to be around 0.5-0.6, which is significant, but is too low to be considered a comprehensive armour solution. The majority of light anti-tank grenades, including the HEAT grenades for weapons such as the LAW, LRAC F1, PzF 44, older grenades for the Carl Gustaf to name just a few, will also be defeated due to warhead destruction when flying between the slats. Only some grenade designs feature a shoulder fuze like the m/66 grenade for the Carl Gustaf.
Maximum Chamber Pressure: 73 MPa
Total Cartridge Mass (incl. propellant charge): 3.49 kg
Projectile Mass: 2.53 kg
Grenade Mass: 1.20 kg
Explosive charge: A-IX-1
Explosive charge mass: 0.322 kg
Muzzle velocity: 400 m/s
Maximum velocity: 665 m/s
Penetration: 300mm RHA
Officially, the PG-9 grenade warhead penetrates 300mm of RHA steel, but this figure actually indicates the thickness of armour that can be perforated with a significant destructive post-perforation effect. This effect is provided when a certain amount of armour overmatch is included. According to a 1979 Soviet report titled "Выбор Кумулятивных Снарядов Для Испытания Брони" (Selection of Cumulative Shells for the Evaluation of Armour), the average penetration of the PG-9 warhead in RHA reaches 326mm. The maximum penetration is 346mm and the minimum penetration is 302mm.
The high penetration power of the PG-9 grenade relative to its caliber can be credited to the large standoff distance of 258mm, or 4.2 calibers, built into the warhead design. This is much higher than the built-in standoff provided for most other HEAT warheads.
In theory, the PG-9 grenade was fully capable of reliably defeating the frontal armour any NATO tank that it was expected to encounter in a major European war during the period of influence of the BMP-1, including tanks such as the M60A1, AMX-30, Leopard 1 and Chieftain. Even when NATO obtained a numerically relevant quantity of next-generation tanks like the Leopard 2 and M1 Abrams in the mid-1980's, the large number of legacy tanks serving in the ground forces of NATO militaries allowed the BMP-1 to stay relevant with the PG-9. However, the small margin of defeat against the front of heavily armoured tanks such as the M60A1 and Chieftain made the PG-9 an unreliable weapon.
The ballistic performance of PG-9 is quite good for a grenade of its class. It has a ballistic coefficient of 2.11. Because of the very high velocity of the rocket grenade, it takes only 1.32 seconds to reach a target at 700 meters. This makes it easier to hit a moving target compared to a lower velocity round. A firing table for the PG-9 round is shown below.
The first column is distance in meters (in meters), the second column is angle of gun elevation (in degrees), the second is the height of drop (in meters), the third is the total flight time (in seconds), and the fifth column is the speed of the rocket grenade (in meters/second). As you can see from the table, the grenade remains supersonic up to 900 meters and slightly further, and the ballistic drop is less than a meter at a distance of 500 meters, and it takes only 0.9 seconds for the grenade to reach its mark at 500 meters.
One of the peculiarities of rocket-propelled grenades like the PG-9 is that the deflection dynamics of the projectile from crosswinds will change depending on the state of the rocket engine. When the projectile is still experiencing acceleration from the rocket engine, it accelerates against the direction of the crosswind. In other words, if the crosswind is blowing from right to left, the projectile flies to the right. Once the rocket engine burns out completely, the projectile begins to decelerate and it behaves like a typical fin-stabilized projectile in the cross wind, which is to say that it flies in the direction of the wind. For the PG-9 round, the rocket engine burns out in only a fraction of a second and as such, the projectile ceases to accelerate against the crosswind and begins to normalize in the opposite direction. At 800 meters, the projectile is completely normalized and is oriented parallel to the bore axis of the cannon, and beyond 800 meters, the projectile becomes deflected into the crosswind. These non-intuitive flight characteristics make it extremely difficult to engage targets at ranges beyond 800 meters as the gunner is expected to mentally apply corrections for this phenomenon without the aid of any instruments except the markings in his sight.
The firing table for PG-9 as fired from the "Grom" shows that the maximum deflection from a 10 m/s crosswind is 6.5 mils at a distance of 500 to 600 meters. Beyond this range, the trajectory of the projectile reverses direction. At 1,150 meters, the point of impact coincides exactly with the point of aim.
Fortunately, because the maximum effective range against tanks is limited to 800 meters, the reversal in the flight direction of the PG-9 grenade in a crosswind at beyond 800 meters is practically irrelevant. The gunner would only need to apply the basic - and more intuitive - windage corrections when firing at virtually all point targets.
Introduced in 1973, the PG-15VS round with the PG-9S grenade featured an improved warhead, providing superior penetration power while maintaining the same weight as the original PG-9S. The new warhead has a shaped charge liner made from V-95 aluminium alloy constructed using new high-precision manufacturing technologies, and the shaped charge was filled with a more powerful OKFOL explosive charge instead of A-IX-1. OKFOL is composed of 95% HMX and 5% phlegmatizing wax. The PG-15VS1 round had the PG-9S1 grenade. It was a cheaper alternative that featured a modified aluminium shaped charge liner and an A-IX-1 filling. It had a lower penetration power than the PG-9S grenade, but it was an improvement over the basic PG-9. Compared to a copper or steel liner, the penetration power of an aluminium-lined shaped charge is inferior, as the jet will bore a wider but shallower penetration cavity. However, this also results in drastically improved post-perforation damage due to the combination of increased ejecta and internal overpressure from the grenade blast. At the same time, the PG-9S and PG-9S1 grenades manage to achieve an excellent penetration performance by having a very long built-in standoff distance, giving its aluminium shaped charge the necessary conditions to achieve performance equal to much larger caliber HEAT shells with copper and steel liners.
All other parts of the PG-15VS and PG-15VS1 rounds were identical to the PG-15V and its ballistic characteristics were identical to that of the PG-9. As such, the 1PN22M1 sight did not need to have a new viewfinder disc to be compatible with the new ammunition. PG-15VS replaced the PG-15V in the early 1970's.
According to the study "Противокумулятивная Стойкость Комбинированных Преград С Керамикой" published in the March 1988 issue of the "Вестник Бронетанковой Техники" military science journal, the penetration channel depth produced by the PG-9S grenade into a semi-infinite RHA block is 404mm ±20mm, based on a sample size of 8 detonations. It was noted in the paper that the penetration depth was determined based on the results of experiments with a confidence level of 95%, and the confidence interval is 384mm to 424mm. However, the standoff distance used was 185mm, which is the distance between the liner and the nose of the warhead without the protruding tip of the VP-9 fuze. This may be enough to simulate the minor reduction in standoff during fuze activation and jet formation as the grenade impacts a target.
The substantial increase in armour penetration performance offered by the PG-15VS increased the probability of knocking out existing tanks with the first shot due to the increased post-perforation effect. With a nominal armour penetration of 400mm RHA, the PG-9S grenade warhead was equivalent in power to the 125mm warhead of the 9M14 "Malyutka" missile, so it was very potent indeed. This improvement was tactically relevant throughout the 1970's because NATO relied entirely on tanks with conventional steel armour that was generally not thick enough to resist any contemporary HEAT weapon worth mentioning. When the Abrams and Leopard 2 were introduced in 1980 and 1979 respectively, one of the basic requirements of their protection was to be immune to a HEAT grenade with the penetration power of the PG-9S within a large frontal arc. For the M1 Abrams specifically, this frontal arc was 90 degrees in size (± 45 degrees). This severely limited the effectiveness of the PG-9S grenade in a frontal attack, making it useful only in a side attack where the angle of impact against the side armour of the tank was less than 45 degrees.
Grenade Mass: 1.20 kg
Explosive charge: A-IX-1
Explosive charge mass: 0.322 kg
Muzzle velocity: 400 m/s
Maximum velocity: 665 m/s
Penetration: 300mm RHA
Officially, the PG-9 grenade warhead penetrates 300mm of RHA steel, but this figure actually indicates the thickness of armour that can be perforated with a significant destructive post-perforation effect. This effect is provided when a certain amount of armour overmatch is included. According to a 1979 Soviet report titled "Выбор Кумулятивных Снарядов Для Испытания Брони" (Selection of Cumulative Shells for the Evaluation of Armour), the average penetration of the PG-9 warhead in RHA reaches 326mm. The maximum penetration is 346mm and the minimum penetration is 302mm.
The high penetration power of the PG-9 grenade relative to its caliber can be credited to the large standoff distance of 258mm, or 4.2 calibers, built into the warhead design. This is much higher than the built-in standoff provided for most other HEAT warheads.
In theory, the PG-9 grenade was fully capable of reliably defeating the frontal armour any NATO tank that it was expected to encounter in a major European war during the period of influence of the BMP-1, including tanks such as the M60A1, AMX-30, Leopard 1 and Chieftain. Even when NATO obtained a numerically relevant quantity of next-generation tanks like the Leopard 2 and M1 Abrams in the mid-1980's, the large number of legacy tanks serving in the ground forces of NATO militaries allowed the BMP-1 to stay relevant with the PG-9. However, the small margin of defeat against the front of heavily armoured tanks such as the M60A1 and Chieftain made the PG-9 an unreliable weapon.
The ballistic performance of PG-9 is quite good for a grenade of its class. It has a ballistic coefficient of 2.11. Because of the very high velocity of the rocket grenade, it takes only 1.32 seconds to reach a target at 700 meters. This makes it easier to hit a moving target compared to a lower velocity round. A firing table for the PG-9 round is shown below.
The first column is distance in meters (in meters), the second column is angle of gun elevation (in degrees), the second is the height of drop (in meters), the third is the total flight time (in seconds), and the fifth column is the speed of the rocket grenade (in meters/second). As you can see from the table, the grenade remains supersonic up to 900 meters and slightly further, and the ballistic drop is less than a meter at a distance of 500 meters, and it takes only 0.9 seconds for the grenade to reach its mark at 500 meters.
One of the peculiarities of rocket-propelled grenades like the PG-9 is that the deflection dynamics of the projectile from crosswinds will change depending on the state of the rocket engine. When the projectile is still experiencing acceleration from the rocket engine, it accelerates against the direction of the crosswind. In other words, if the crosswind is blowing from right to left, the projectile flies to the right. Once the rocket engine burns out completely, the projectile begins to decelerate and it behaves like a typical fin-stabilized projectile in the cross wind, which is to say that it flies in the direction of the wind. For the PG-9 round, the rocket engine burns out in only a fraction of a second and as such, the projectile ceases to accelerate against the crosswind and begins to normalize in the opposite direction. At 800 meters, the projectile is completely normalized and is oriented parallel to the bore axis of the cannon, and beyond 800 meters, the projectile becomes deflected into the crosswind. These non-intuitive flight characteristics make it extremely difficult to engage targets at ranges beyond 800 meters as the gunner is expected to mentally apply corrections for this phenomenon without the aid of any instruments except the markings in his sight.
The firing table for PG-9 as fired from the "Grom" shows that the maximum deflection from a 10 m/s crosswind is 6.5 mils at a distance of 500 to 600 meters. Beyond this range, the trajectory of the projectile reverses direction. At 1,150 meters, the point of impact coincides exactly with the point of aim.
Fortunately, because the maximum effective range against tanks is limited to 800 meters, the reversal in the flight direction of the PG-9 grenade in a crosswind at beyond 800 meters is practically irrelevant. The gunner would only need to apply the basic - and more intuitive - windage corrections when firing at virtually all point targets.
PG-15VS, PG-15VS1
Introduced in 1973, the PG-15VS round with the PG-9S grenade featured an improved warhead, providing superior penetration power while maintaining the same weight as the original PG-9S. The new warhead has a shaped charge liner made from V-95 aluminium alloy constructed using new high-precision manufacturing technologies, and the shaped charge was filled with a more powerful OKFOL explosive charge instead of A-IX-1. OKFOL is composed of 95% HMX and 5% phlegmatizing wax. The PG-15VS1 round had the PG-9S1 grenade. It was a cheaper alternative that featured a modified aluminium shaped charge liner and an A-IX-1 filling. It had a lower penetration power than the PG-9S grenade, but it was an improvement over the basic PG-9. Compared to a copper or steel liner, the penetration power of an aluminium-lined shaped charge is inferior, as the jet will bore a wider but shallower penetration cavity. However, this also results in drastically improved post-perforation damage due to the combination of increased ejecta and internal overpressure from the grenade blast. At the same time, the PG-9S and PG-9S1 grenades manage to achieve an excellent penetration performance by having a very long built-in standoff distance, giving its aluminium shaped charge the necessary conditions to achieve performance equal to much larger caliber HEAT shells with copper and steel liners.
All other parts of the PG-15VS and PG-15VS1 rounds were identical to the PG-15V and its ballistic characteristics were identical to that of the PG-9. As such, the 1PN22M1 sight did not need to have a new viewfinder disc to be compatible with the new ammunition. PG-15VS replaced the PG-15V in the early 1970's.
The substantial increase in armour penetration performance offered by the PG-15VS increased the probability of knocking out existing tanks with the first shot due to the increased post-perforation effect. With a nominal armour penetration of 400mm RHA, the PG-9S grenade warhead was equivalent in power to the 125mm warhead of the 9M14 "Malyutka" missile, so it was very potent indeed. This improvement was tactically relevant throughout the 1970's because NATO relied entirely on tanks with conventional steel armour that was generally not thick enough to resist any contemporary HEAT weapon worth mentioning. When the Abrams and Leopard 2 were introduced in 1980 and 1979 respectively, one of the basic requirements of their protection was to be immune to a HEAT grenade with the penetration power of the PG-9S within a large frontal arc. For the M1 Abrams specifically, this frontal arc was 90 degrees in size (± 45 degrees). This severely limited the effectiveness of the PG-9S grenade in a frontal attack, making it useful only in a side attack where the angle of impact against the side armour of the tank was less than 45 degrees.
Additionally, according to the book "Боеприпасы И Средства Поражения: Энциклопедия XXI век" (Ordnance and Means of Destruction: Encyclopedia of the 21st Century), the penetration of the PG-15VS in brick is 1.5 meters, and its penetration in reinforced concrete is 1 meter.
PG-15VS (PG-15VS1)
Total mass (incl. propellant charge): ~3.49 kg
Explosive charge: OKFOL (A-IX-1)
Explosive charge mass: 0.340 kg (0.316 kg)
Muzzle velocity: 400 m/s
Maximum velocity: 665 m/s
Penetration: 400mm RHA (350mm RHA)
Soviet-era stocks of PG-15V rockets have either been used up or have expired, and production for domestic use in Russia has shifted towards the improved PG-15VS for equipping the meager collection of various leftover BMP-1s still in service in rear echelon forces. Since 1999, the Planta chemical plant in Russia has been proceeding with its munitions recycling program designed to reintroduce expired Soviet-era HEAT grenades back into the Russian Armed Forces. Up to 75% of all non-perishable components (including the casing, booster assembly, shaped charge liner, fuze, etc.) could be kept and reused with new rocket propellant and a new explosive charge.
The remaining BMP-1P vehicles still in use in the Russian Army are armed with PG-15VS or PG-15VS1 rounds, as this is the type that is also supplied for the SPG-9 recoilless guns that are present in the Army.
Introduced in 1973, the OG-15V round gave the BMP-1 a greatly enhanced anti-personnel capability. With these HE-Frag rounds and HEAT grenades, a BMP-1 was theoretically capable of fulfilling all combat tasks from eliminating infantry in the open and in field fortifications, to destroying tanks. As the OG-15V was significantly shorter than PG-15V, it cannot be loaded by the BMP-1 autoloader but it is much easier to load by hand within the confines of the turret.
PG-15VS (PG-15VS1)
Total mass (incl. propellant charge): ~3.49 kg
Explosive charge: OKFOL (A-IX-1)
Explosive charge mass: 0.340 kg (0.316 kg)
Muzzle velocity: 400 m/s
Maximum velocity: 665 m/s
Penetration: 400mm RHA (350mm RHA)
The remaining BMP-1P vehicles still in use in the Russian Army are armed with PG-15VS or PG-15VS1 rounds, as this is the type that is also supplied for the SPG-9 recoilless guns that are present in the Army.
OG-15V (HE-Frag)
Introduced in 1973, the OG-15V round gave the BMP-1 a greatly enhanced anti-personnel capability. With these HE-Frag rounds and HEAT grenades, a BMP-1 was theoretically capable of fulfilling all combat tasks from eliminating infantry in the open and in field fortifications, to destroying tanks. As the OG-15V was significantly shorter than PG-15V, it cannot be loaded by the BMP-1 autoloader but it is much easier to load by hand within the confines of the turret.
Ballistically, the OG-9 grenade is similar to a mortar shell. It is significantly heavier than a PG-9 grenade and it lacks a rocket motor. Because of this, it is subsonic, with a muzzle velocity of just 290 m/s. Unlike the four long flip-out stabilizing fins of the PG-9 rocket grenade, the eight stabilizing fins on the OG-9 have a much smaller wingspan and gives the grenade the ballistics of a mortar bomb fired at a full charge. Firing tables show that in a 10 m/s crosswind, an OG-9 grenade is deflected by 3 meters.
When the OG-9 grenade is fired with the safety cap on, the fuze is switches from instantaneous impact initiation to inertial initiation, giving the grenade a short delay to allow it to function in the HE mode. When the safety cap is removed prior to firing, the grenade functions in the Frag mode. The need to manually set the fuze mode is one of the reasons why the autoloader of the BMP-1 is not used to load the OG-15V grenade.
The OG-9G warhead of the grenade has a 0.73 kg filler of A-IX-1. The explosiveness of A-IX-1 is 1.58 times higher than TNT. This is quite good, but it is still slightly lower than pure hexogen due to the presence of a wax phlegmatizer to stabilize the explosive compound. In terms of explosive effect, the OG-9G warhead is equivalent to 1.15 kg of TNT. This is almost twice that of tank-fired 75mm and 76mm HE shells.
Like the PG-9, the OG-9 grenade uses the same PG-15P propellant charge. The grenade body has a perforated tube section in lieu of a rocket motor. When the PG-15P charge is detonated, the perforated tube of the grenade fills with expanding gasses which results in a reduction in chamber pressure. Due to the low muzzle velocity and the lack of a rocket motor, the OG-15V has a very pronounced arcing ballistic trajectory, similar to a mortar bomb.
The original video is available here (link).
Muzzle velocity: 290 m/s
Total Cartridge Mass (incl. propellant): 4.59 kg
Warhead Total Mass: 3.7 kg
Explosive charge: A-IX-1
Explosive charge mass: 0.73 kg
The cast steel casing of the warhead weighs 2.83 kilograms. The walls of the warhead cavity can be seen in the photo below. Photo by RaiderBox. With a TNT equivalence of 1.15 kg, the mass of the filler is 40% of the mass of the steel casing. The mass of the explosive charge is quite large for a grenade of its caliber, but the thickness of the steel casing is considerably less than a tank-fired HE shell of a similar caliber. For comparison, the steel casing of the M309 HE shell weighs 5.35 kg. Due to the use of cast steel rather than forged steel, made possible by the low velocity of the grenade, and the relatively thin casing walls, the fragmentation effect is likely to be excellent.
The OG-9G warhead of the grenade has a 0.73 kg filler of A-IX-1. The explosiveness of A-IX-1 is 1.58 times higher than TNT. This is quite good, but it is still slightly lower than pure hexogen due to the presence of a wax phlegmatizer to stabilize the explosive compound. In terms of explosive effect, the OG-9G warhead is equivalent to 1.15 kg of TNT. This is almost twice that of tank-fired 75mm and 76mm HE shells.
Like the PG-9, the OG-9 grenade uses the same PG-15P propellant charge. The grenade body has a perforated tube section in lieu of a rocket motor. When the PG-15P charge is detonated, the perforated tube of the grenade fills with expanding gasses which results in a reduction in chamber pressure. Due to the low muzzle velocity and the lack of a rocket motor, the OG-15V has a very pronounced arcing ballistic trajectory, similar to a mortar bomb.
The original video is available here (link).
Muzzle velocity: 290 m/s
Total Cartridge Mass (incl. propellant): 4.59 kg
Warhead Total Mass: 3.7 kg
Explosive charge: A-IX-1
Explosive charge mass: 0.73 kg
The cast steel casing of the warhead weighs 2.83 kilograms. The walls of the warhead cavity can be seen in the photo below. Photo by RaiderBox. With a TNT equivalence of 1.15 kg, the mass of the filler is 40% of the mass of the steel casing. The mass of the explosive charge is quite large for a grenade of its caliber, but the thickness of the steel casing is considerably less than a tank-fired HE shell of a similar caliber. For comparison, the steel casing of the M309 HE shell weighs 5.35 kg. Due to the use of cast steel rather than forged steel, made possible by the low velocity of the grenade, and the relatively thin casing walls, the fragmentation effect is likely to be excellent.
The OG-9G warhead is considerably more potent than 82mm mortar bombs in terms of explosive payload and casing weight, and has a superior filling to weight ratio. For example, the VO-832DU mortar bomb, used as a standard bomb for all Soviet mortars since the 82mm mortar Mod. 1937, has a full bomb weight of 3.1 kg and a TNT filler weighing just 0.4 kg. The superiority of OG-9G is entirely due to the higher elongation of its warhead.
It is also worth mentioning that the OG-9 grenade is launched at around the same velocity as a typical mortar bomb, except that the poor gun elevation of the 2A28 cannon in the BMP-1 restricts its ability to perform long range indirect fire. It is only possible to use the grenade in the direct fire mode. The closest counterpart to this unique combination is the M20 recoilless rifle firing the spin-stabilized M309 HE shell, but the M309 is a modification of the tank-fired M48 shell of WWII vintage. The nominal kill zone of the OG-9 grenade is 83 square meters against infantrymen in the prone or supine position. For comparison, a 30mm HE-I shell has a nominal kill zone of 11 square meters against the same targets. The nominal kill zone of OG-9 is 500 square meters against infantrymen in a standing position.
Although the OG-9 grenade is primarily intended for the anti-personnel and anti-fortification role, they can also be effective against lightly armoured vehicles and soft-skinned vehicles under certain conditions. The photo on the left is from the 15th Artillery Field Regiment website and shows an M113 hit by a B40 anti-tank grenade launcher (RPG-2 clone). The photo on the right is from the Australian War Memorial website and shows a destroyed Australian M113A1 from the Vietnam War. According to the AWM, the vehicle was hit three times by 75mm recoilless rifles during Operation Bribie on the 17th of February 1967. In both photos, it is simple to deduce that the large breaches in the armour were caused by an external explosion because the edges of the armour plate around the breach are bent inward. This implies that the explosive payload of grenades in the 70-80mm caliber range is already sufficient to cause serious damage to lightly armoured vehicles.
The second example is the most interesting because one of the 75mm recoilless rifle rounds struck the passenger compartment roof hatch which was open at the time, and the damage done by the HEAT grenade to the 38mm-thick hatch can be clearly seen. The engine of the M113A1 was destroyed by another round from recoilless rifles. Note that the 75mm M309 HE grenade fired from the M20 recoilless rifle only has 0.676 kg of TNT as its explosive filler and the projectile is launched at a muzzle velocity of just 302 m/s, and the HEAT grenade has even less explosive power. The OG-9 grenade is launched at practically the same muzzle velocity but the explosive charge of its warhead is equivalent to 1.15 kg of TNT. The heavier steel casing of the M309 is irrelevant in this comparison as it is the blasting power of the shell that caused the damage to this M113 and not fragmentation.
Although HEAT rounds are usually the ammunition of choice when grenadiers are facing armoured vehicles, it is clear that even medium-caliber high explosive shells launched at low velocities can cause enough damage to knock out armoured personnel carriers and other vehicles with a similar level of armour protection. With this in mind, it should be understood that the addition of HE rounds as a new ammunition type to the repertoire of the BMP-1 in 1974 did not necessarily result in a trade-off of anti-armour capabilities in exchange for enhanced anti-personnel and anti-fortification capabilities. Rather, the overall firepower and flexibility of the BMP-1 saw a general increase.
The OG-15VM grenade became available later on. It was an improved version using a more powerful A-IX-2 explosive charge instead of A-IX-1. This improved the blasting power of the warhead and added an enhanced incendiary effect.
PKT
Although the coaxial machine gun in most IFVs is usually sidelined in favour of their more powerful autocannons when engaging infantry, the BMP is often forced to depend on its PKT when dealing with infantry in the open due to the weak fragmentation effects of the 73mm HEAT grenades. The PKT is mounted to the right of the 73mm 2A28 "Grom" cannon, as it feeds from the right and ejects to the left.
To facilitate the work of the gunner, the coaxial machine gun in the BMP was fed from an unusually large 2,000 round box as the drawing below shows. This was a departure from the typical ammunition feed systems for the coaxial machine guns of Soviet tanks and armoured personnel carriers. As the BMP must make use of its PKT regularly, the large capacity box is very convenient. Looking abroad, however, it is clear that this was not much of an innovation for 1967. The Marder 1 and the AMX-10 were both introduced in the early 1970's and both had coaxial machine guns fed with 2,000-round boxes, so the BMP can be considered on par with its contemporaries in this regard. Also, the BMP carries additional boxes of machine gun ammunition, but those boxes are meant for hand-held PK and PKM machine guns and cannot be readily used by the coaxial machine gun, as there is no mounting point for 250-round boxes, although it is still possible to load a full belt and leave it hanging - the PK series reportedly has an exceptionally strong feeding mechanism.
Spent shell casings and link segments fall through a chute and into a metal bin to be collected. This bin is the same one that collects spent casings ejected from the main cannon, but in a different compartment.
If stoppages occur, the gunner - being the only occupant of the turret - is responsible for correcting them. It is fairly easy to do so due to the close proximity of the machine gun to the gunner's seat even though it is installed to the right of the 2A28 cannon.
Armour piercing incendiary rounds and armour piercing incendiary tracer ammunition is usually loaded in a 4:1 ratio. The PKT machine gun has a cyclic rate of fire of 650 rounds per minute, and it has a thicker barrel than the infantry-based PK to allow for longer periods of sustained fire. There are two ways to fire the PKT: the left thumbs witch on the control handles, or by depressing the manual trigger lever on the back of the machine gun, on the firing unit just behind the disassembly button.
In 1969, the PK was replaced by the PKM and the corresponding sub-variants were also replaced with modifications of the PKM, including the replacement of the PKT with the PKTM. The PKTM is mainly distinguished from the earlier PKT by the smooth barrel as opposed to the fluted barrel of the PKT. Internally, the PKTM and the PKT differ in the same way that the basic PK and PKM models differ.
BMP-1 (Object 765 sp.1, sp.2, sp.3)
"MALYUTKA" ATGM SYSTEM
The 9M14 "Malyutka" missile entered service in 1963 as part of the 9K11 system. At the time of the introduction of the BMP-1, the 9K11 "Malyutka" ATGM system was already widespread in the Soviet Army as an infantry-operated system and it posed a a very serious threat to NATO armour despite the inherent limitations of its manual guidance principle. Owing to its high performance characteristics despite its dimunitive size, it was viable for both infantry and mounted systems, including dedicated missile carriers, but for the BMP, the most significant aspect was that it was the first ATGM system to be comprehensively incorporated as part of the primary armament of this class of combat vehicle. This was one of the reasons why the BMP-1 is often said to be more qualified as the first true IFV instead than the Schützenpanzer 12-3 which came much earlier, despite the fact that the Bundeswehr had developed mechanized infantry tactics centering on the IFV concept to go with the SPz 12-3 before the Soviet Army. Even the Marder 1 that entered service years after the BMP did not feature an ATGM launching capability.
When the BMP-1 entered service in 1966, the original 9M14 missile had been replaced by the improved 9M14M "Malyutka-M". In a 1966 manual for the BMP-1 (Object 765 sp.1), the 9M14M is the specified model in a standard combat load and the descriptions and instructions in the manual all pertain to the 9M14M only, with no mention of the 9M14 whatsoever. Although the older 9M14 could be fired from the BMP-1 without any compatibility issues, it is safe to assume that it was not officially issued to the BMP-1 during its service in the Soviet Army. The "Malyutka" series and its technical details are described in a separate Tankograd article, "Soviet ATGMs".
Owing to the demanding requirements set forth in a government decree on July 6, 1961, the 9M14 "Malyutka" missile that entered service in 1963 surpassed all of its foreign counterparts. One of the requirements was for the missile to have a weight of 8-10 kg to ensure that it could be transported easily by infantry anti-tank teams, and although the final product went slightly over the limit with a weight of 10.9 kg, it was still light enough for the specified role. Moreover, its relatively small dimensions and foldable fins made it much more convenient to transport, especially in fully enclosed vehicles where compactness was a particularly important factor. The closest counterpart to the 9M14 was the French ENTAC missile, which is comically oversized and overweight in comparison with the more sophisticated "Malyutka" despite belonging to the same class of ATGM.
When installed on the launcher atop the 2A28 cannon and deployed for launch, the 9M14M missile on the BMP-1 is completely exposed and may be damaged. The lack of protection from gunfire and shell fragments was an important consideration, but it was also recognized that the missile could potentially be rendered inoperable in mundane accidents such as in a collision with a tree branch that causes one of the plastic stabilizer fins to break.
To prevent this type of damage, it was officially forbidden for BMP-1 gunners to keep a missile deployed on the external launcher indefinitely. When going on a march, the launcher would be kept empty and all missiles would be stowed internally. The gunner would only load a missile onto the launcher if it was necessary during combat or if combat was imminent and there was a perceived need.
The missile comes assembled with a lightweight launch rail that fits onto the launcher on top of the cannon barrel. It is the same launch rail used in the 9P110 and 9P133 tank destroyers. After a missile is launched, the launch rail remains on the launch platform and it must be manually removed by the gunner before the next missile is loaded. The launch rail would be reused when replenishing the ammunition supply of the vehicle. New missiles are attached to the launch rail before they are stowed in the BMP.
The "Malyutka" launch platform contains electrical connectors that joins the missile guidance system to the missile guidance wire through the launch rail. The missile guidance wire not only transmits steering commands from the operator's joystick to the missile, but also serves as an electrical conduit that supplies the missile with electrical power. The launch platform positions the launch rail at an elevation angle of 3.25 degrees.
During the launch and throughout the flight of the missile, it maintains a spin rate of 8.5 revolutions per second. Although the performance of shaped charge warheads is negatively affected by spin, this modest rate of spin was far too low to have a noticeable effect on the performance of the missile warhead.
Among the requirements for the 9M14 missile was that it must penetrate between 180-200mm of RHA steel at an angle of 60 degrees. The final warhead design managed to achieve a penetration of 200mm RHA, which makes it a direct equivalent to the 9M17P "Fleyta-P" missile. Despite the 9M17P having a larger warhead diameter of 142mm, the smaller 125mm warhead of the "Malyutka" could match its performance thanks to a much larger standoff distance built into the missile fairing.
When launching a missile, the cannon should be elevated to provide the necessary ground clearance to allow the missile to stabilize during flight. The correct elevation is achieved by the gunner placing the crosshair at the bottom of the 1PN22M1 sight viewfinder on the desired target.
Control of the "Malyutka" missile is achieved using the 9S428 control system which includes the analogue electronic components of the control joystick for the gunner and the electrical connections that connect the missile to the launching system on top of the barrel of the "Grom" cannon.
Control of the "Malyutka" missile is MCLOS only, and that means that the gunner must steer the missile manually as it flies through the air. This is done via the 9V332 missile systems control box, which has a joystick to steer and a button to launch the missile. When not in use, the joystick is retracted inside the control box. The 9V332 missile systems control box was originally designed for the 9P110 tank destroyer. The box has a non-functioning dial that was originally meant to allow the 9P110 missile operator to select a missile from the six available on the overhead launch rails. As the BMP-1 can only mount one missile at a time, the dial is permanently set at the number one position. To launch a missile, the gunner presses the "launch" button on the left of the control box. The purple bulb in the center of the box is the missile status indicator. If the bulb does not light up, it means that the missile is either not mounted, not mounted properly, or malfunctioning.
To use the control box, the joystick is extended first. For the best results, the joystick is grasped with both hands and the gunner presses his thumbs against the tip of the joystick to input small corrections when steering the missile. When the joystick is deflected in the four cardinal directions, the missile acquires a directional acceleration corresponding to the deflection angle of the joystick. For example, if the joystick was merely tapped to the left, the missile accelerates a small amount to the left, and if the joystick was pushed to its maximum deflection to the left, the missile accelerates very quickly to the left. The missile maintains its speed after it is steered, so if the gunner returns the joystick to the neutral position, the missile will continue to drift in the direction it was previously steered. The gunner must input a correction in the opposite direction to return the missile to a straight trajectory.
When a missile is in flight, the gunner is supposed to concentrate on guiding the missile to the target but there are no technical limitations that prevent the gunner from firing the 2A28 cannon or the coaxial machine gun. The missile control system and the turret controls are not linked.
The control box is installed on a hinged pedestal. When not in use, the box is stowed away by swinging the pedestal underneath the gunner's seat.
GUIDANCE METHOD
The 9M14M "Malyutka-M" missiles launched from the BMP-1 were to be guided by the gunner using the same three-point method as the missile operators of any other MCLOS missile system. The three-point method includes three reference points, which are the operator, the missile, and the target. The operator tracks the missile and target and attempts to guide the missile into the target while ensuring that the missile never touches the ground, as opposed to a typical SACLOS system where the operator only has to track the target.
The proper control methods for an MCLOS missile like the 9M14M are detailed in a 1967 Polish article titled "Szkolenie operatorów przeciwpancernych pocisków kierowanych" (Training of anti-tank guided missile operators). The most relevant parts of the article have been extracted below, but the original text can be accessed in this post on the Milimoto blog.
Figure 10a shows the perfect way to control the missile. It is considered as such because it ensures that the missile never comes in contact with the ground or any bushes or fences on the ground situated between the operator and the intended target. The operator in this case would control the missile at a certain height above ground level and then he would lower it to the line of sight just before it impacts the target. However, this guidance method is not practical for an MCLOS missile as this would require the operator to know the distance between the missile and the target at every point on the flight path, and without a rangefinder on the BMP-1, this was not feasible. Therefore, this guidance method could not be used. It is worth noting that years later, the T-64B obr. 1976 implemented the highly advanced "Kobra" ATGM system with a SACLOS guidance system that attained this trajectory with the use of a guidance computer and the integrated laser rangefinder in the tank's 1G42 sight.
Figure 10 (b), (c) and (d) show the best ways to guide a missile over various distances. These methods rely on the fact that the missile's flight is gradually lowered to the operator's line of sight with the target at a certain time, just before it impacts the target. From point P2 of the trajectory shown in the drawings above, the projectile is guided by the three-point method (eye-missile-target) in the so-called attack phase where the missile is in the operator's line of sight with the target. When operating a missile in this phase, the operator must focus his attention and steadily steer the missile. The missile is most likely to touch the ground in this phase.
It is understandable that from the point of view of the operator's psychological capabilities, the attack phase should be as short as possible. In addition, it was calculated that the probability of the missile coming into contact with the ground increases with the passage of the projectile's flight time in the operator's line of sight (because it travels at its minimum altitude during this time). Therefore, guidance time using the three points method at different shooting distances will be different, which will involve the operator having to perform appropriate tracking and flight time assessment activities.
While observing the firing of an ATGM, there were many cases where operators found a lack of psychological resistance under the influence of emotional tension in guiding the missile while it was approaching the target. Some, under the influence of mental illusions, sought to bring the missile to the line of sight as soon as possible (eye-missile-target). In addition, the operator's high emotional tension led to the fact that such shooting usually ended with a missile hitting the ground. Operators who learned the technique of controlling an ATGM and adhered to the rules of approaching the target during the specified time and at the appropriate height, were able to properly stabilize the missile and smoothly enter the attack phase.
When engaging a target situated at a distance of more than 500 meters up to 1,000 meters, the gunner can guide the missile using only his forward-facing TNPO-170A general vision periscope. When the target is further than a kilometer away, it is much more practical to switch to the primary sight as there is much more time for the missile to be captured within the field of view of the gunner. The gunner determines which method to use by first estimating the range to the target using the stadia rangefinder incorporated in his 1PN22M1 sight.
The 6x magnification and the field of view of 15 degrees of the 1PN22M1 sights in the BMP-1 was more than enough to find and engage targets at the maximum aiming range of 1,300 meters of the PG-9 grenade, and based on Soviet requirements, it was also sufficient for finding and engaging targets at 3,000 meters. According to Soviet data, an optical sight with no magnification would allow the gunner to see and identify a tank from a distance of 1.0-1.5 kilometers, while an optical sight with 5x magnification would allow a gunner to do so from 3.0 kilometers. Other data indicates that an optical sight with a magnification of 7-8x would allow a tank to be identified from a distance of 4.0-5.0 kilometers. As such, the magnification of the 1PN22M1 can be considered sufficient for a BMP-1 gunner to fully exploit the maximum range of the 9M14M missile against tanks and other targets of a similar size.
Nevertheless, it should be noted that a higher magnification would be preferable due to the demanding nature of the MCLOS missile guidance principle. Besides the obvious advantage of being able to identify a camouflaged tank at long range more easily with a higher magnification sight, a more enlarged view of the target and the missile would also allow the gunner to steer the missile more precisely. In this regard, the 9K11 man-packed missile complex had an advantage due to the 8x magnification of its 9Sh16 periscopic sight.
MISSILE LAUNCH
It should be noted that because the missile is launched from a rail on top of the gun barrel of the 2A28 "Grom", it will be clear of any obstacles as long as the gunner has a clear line of sight to the target from his primary sight. The gunner can verify this using his general vision periscopes. Moreover, because the missile is launched at a slight elevation angle such that it gains altitude immediately upon leaving the launch rail, it is guaranteed that there will be enough ground clearance to ensure that the stabilizer fins do not touch the ground.
With the gunner's periscopic primary sight and his forward-facing general vision periscopes all on the turret roof and the missile itself being above it, it is possible for a BMP-1 gunner to launch and guide his missiles from a turret defilade position. This is a capability that the BMP-1 shares with missile tank destroyers like the 9P110.
Due to the elevated launch angle built into the 9M14 and 9M14M missile launch system, the initial 500 meters traveled by the missile after its launch is a dead zone where it is not yet under the complete control of the operator. It is not impossible to hit a target inside this dead zone, but it is very unlikely in combat conditions and should not be attempted unless it is an emergency situation as it would otherwise be a waste of ammunition. An absolute minimum range is set by the warhead fuze which is only armed after the missile has traveled 70-200 meters. Engaging targets inside the 500-meter practical dead zone of the missile is done using the 73mm 2A28 cannon. Even without the dead zone, it is always favourable for a BMP-1 gunner to engage it with his cannon instead of an MCLOS missile as the reaction time with the cannon tends to be quicker.
It is often stated that the dead zone exists as a consequence of the limitations of the MCLOS guidance principle, but this is not true. The dead zone exists because of a combination of the waiting time for sustainer engine to start, whereby the thrust vectoring control system becomes active, and the time needed by the missile operator to bring the missile down from altitude to a target at ground level. The 9M14P "Malyutka-P" missile with a SACLOS guidance system had a reduced dead zone of 400 meters thanks to the automatic command unit which is able to visually capture the missile and bring it under control more quickly than a human operator, but the dead zone was inherently quite large due to the peculiarities of the launch system. Later SACLOS missiles like the 9M111 "Fagot" and 9M113 "Konkurs" practically removed the dead zone by implementing a different control mechanism along with a gas generator to launch the missiles at a high initial velocity, thus allowing the missiles to be controlled in direct flight towards the target along the line of sight of the command unit optic immediately after launch.
The operational zone of the 9M14M missile launched from a BMP-1 is much narrower than the same missile launched as part of the 9K11 man-portable complex, but only if the turret of the BMP-1 is not turned to expand the size of the firing arc. Without using the rotation of the turret, the firing arc is only 15 degrees. At a range of 3,000 meters, this arc covers a width of almost 800 meters, so it is enough for slower moving targets such as vehicles being driven cross-country. For the 9K11 complex, the operational width is a whopping 2,240 meters, but this is only achieved if the operator swivels his 9Sh16 periscopic sight. In a BMP-1, the 1PN22M1 sight is fixed to the turret in the horizontal plane, but the gunner can rotate the turret incrementally as the target approaches the edge of his field of view in the sight and thus expand the firing arc of his 9M14M missile to track any moving target.
At night, the 9M14M missile is completely ineffective without external factors to assist the gunner since the night vision module of the 1PN22M1 sight only allows tank-type targets to be identified from a maximum distance of 400 meters with starlight alone. This is less than the practical minimum range of the missile. On a moonlit night with clear skies, it may be possible for a skilled gunner to use the missile, but this is circumstantial. It is only possible to use the missile at night with somewhat consistent results by relying on illumination shells and flares fired over enemy positions. If the opportunity presents itself, gunners can guide a missile towards the light emitted by the headlights of enemy vehicles even in complete darkness.
In the snippet below from the September-October 1975 issue of the Army Reserve magazine, it is stated that in a poll of Israeli tank crews after the 1973 Arab-Israeli war showed that it was extremely difficult to detect the launch of a "Malyutka" missile but most tank commanders could at least detect the missile itself as it traveled towards them. The caveat is that the missiles were detected at long range in only a minority of cases, so while it is reasonable for a "Malyutka" operator to expect a missile launched at an enemy tank to be detected most of the time, it is not feasible to expect the majority of the enemy tank crews to detect the missile until it is already too late to perform evasive maneuvers or to fire back at the launch site.
The chances of detecting incoming missiles in a timely manner may be increased if the crews of multiple tanks in a unit focus their attention in the same area, but on the other hand, those chances may plummet if the tank crew is already preoccupied with fighting other enemy forces.
Based on the experiences of U.S troops in Vietnam, it was possible to distract or agitate the operator of a 9K11 complex by having all nearby personnel fire every weapon available in the general direction of the operator. However, it is reasonable to assume that this tactic was only feasible because of the relatively short combat ranges that were supported by the local environment, and even then, it was not a reliable countermeasure by any means. The same tactic would be even less effective against a BMP-1 gunner who is fully enclosed in an armoured vehicle that offers both physical and psychological protection with a combination of its protection from shell fragments and a certain amount of isolation from the noise of the return fire.
The Hungarian Army estimated that on average, the probability of achieving a hit on a static tank target with an MCLOS "Malyutka" missile was only 20% to 25%. Nevertheless, this modest figure already indicates an advantage over the SS.11 missile which had a recorded probability of hit of 10% based on American experiences in Vietnam during the 1972 Easter Offensive against NVA tanks. Steven J. Zaloga writes in a 1994 article published in Jane's Intelligence Review that a "Malyutka" operator needed to have fired about 2,300 simulated missile shots before he could be qualified. The gunner would also apparently need to practice at the simulator 50 to 60 times a week to maintain that proficiency standard.
Due to the extremely large number of shots needed to train a missile operator to proficiency, the only practical option was to rely heavily on simulators with live fire training sessions occupying a much smaller share of the training regime. Nevertheless, the "Malyutka" series of missiles had an inherent advantage over earlier MCLOS missiles that were steered with spoilers like the 3M6 "Shmel" or the SS.10 instead of a thrust vectoring control system in that the missile was more responsive to the operator's commands. This reduced the chances of the operator accidentally steering the missile into the ground when attempting to guide it onto the target, especially if the target is a tank in a hull defilade position. Needless to say, this was beneficial due to the challenging nature of guiding this type of ATGM, and the relatively high flight velocity of the 9M14M had a generally positive influence on its hit probability as there was less time for the target to evade it.
LOADING MISSILES
The relatively light weight of the 9M14M missile and its small dimensions lent itself quite well to relatively quick and easy loading from within the confines of the turret. Arguably easier even in comparison to later IFV designs like the Bradley which forced a passenger to load TOW missiles weighing in excess of 21 kg from the passenger compartment through a large roof hatch. The Bradley could not reload its missiles at all either if no passengers were around to help. For what it's worth, that is a praiseworthy feature of the BMP-1.
To load a missile, the gunner must elevate the cannon to its limit of +30 degrees, open a small hatch in the turret roof directly above the cannon breech, and then slide the missile with its launch rail onto the launcher. To align the missile launch rail with the launcher, the gunner aligns it on top of a pair of rollers on top of the "Grom" cannon breech before pushing the entire assembly forward.
When the launch rail is pushed forward far enough, it is automatically locked in place. The missile has its stabilizer fins folded for stowage and to fit through the small hatch in the turret roof, so the next step for the gunner is to unfold the fins. The gunner could do this by reaching his arm out of the loading hatch, but to minimize his exposure outside of the armoured turret, he was provided with a special stick.
A standard combat load for a BMP-1 includes four 9M14M missiles, of which two are stowed in a ready rack on the turret floor while the remaining two are stowed next to the turret in the passenger compartment. The ready racks are shown in the photo on the left below, and the location of both the ready and reserve racks in the vehicle from a top-down perspective with an arrow to indicate the front of the hull. While in a 9K11 man-portable system, the warhead of the missile would be detached and stowed separately, and then assembled during setup, but for the BMP-1, the missiles are stowed in their assembled form and require only the wings to be deployed.
The ready racks are in a convenient location for the gunner to rapidly reload the launcher without leaving his seat.
In case of an unexpected sudden contact with enemy forces while a BMP-1 unit is on a march, the gunner cannot react immediately as he must first complete a number of preparations. According to Sergey Suvorov in his book "Боевые машины пехоты БМП-1, БМП-2 и БМП-3. «Братская могила пехоты» или супероружие" (BMP-1, BMP-2 and BMP-3 infantry fighting vehicles. "Mass grave of infantry" or a superweapon), no more than 50 seconds is needed to complete the full preparation process to launch a missile. This process not only includes the loading of the missile itself, but also the setup of the guidance equipment.
Officially, the crew standards for a BMP-1 gunner mandate that the ATGM must be readied and fired within 55 seconds for him to pass with a "satisfactory" mark. To pass with a "good" mark, the procedure must be done within 45 seconds, and to pass with an "excellent" mark, no more than 40 seconds must be taken. The procedure is not equivalent to the loading time of a single 9M14M missile as it also involves the readying of the ATGM control system and other tasks. It is described as follows:
"Обучаемый на месте наводчика-оператора ПТУР на направляющей в боевой укладке, пульт оператора в походпом положении, оружие в боевом положений. При выполнения норматива обучаемый переводит пульт оператора в боевое положеше, устанавливает ПТУР па пусковой кронштейн, наводит пусковую установку в цель и производит пуск ПТУР."Translated:
"The trainee is in the gunner's station. The ATGM mockup is stowed in the fighting compartment, the operator's control box [9V332] is stowed away, the gun [the 2A28] is in a combat position. When executing the drill, the trainee transfers the operator's control box to the combat position, installs the ATGM on the launch bracket, directs the launcher to the target, and launches the ATGM."
To complete the process in reverse, the time taken for a BMP-1 trainee gunner to achieve a "satisfactory" mark is 35 seconds. A time of 30 seconds is required for a "good" mark is 30 seconds, and a time of 25 seconds is required for an "excellent" mark.
Given the preparation times stated in the official standards for trainee gunners, the 50-second time stated by Suvorov is reasonable. In battle, 50 seconds is a very long time and it is only acceptable if there is a long standoff distance between the BMP and the enemy. At long range, the seriousness of the issue is ameliorated to a large extent by the low probability of a direct hit from enemy fire, which is aided by the small silhouette of the BMP-1 itself. At short ranges such as in an ambush scenario, the gunner can react quickly by returning fire with the 2A28 cannon and there is no need to bring the missile into action, but if the target is beyond the effective range of the 2A28 cannon while still remaining close enough to be able to fire upon the BMP-1 with a high probability of hit, then the crew has no options but to have the driver maneuver the vehicle into a covered position.
If the presence of the enemy is known or if enemy contact is determined to be probable, the long-range firepower of the BMP-1 can be maximized by having a missile loaded onto the launch rail from the reserve stowage racks, thus keeping the ready racks full. Ideally, the missiles are used with a considerable standoff distance between the BMP-1 and the target to ensure the greatest probability of survival for the operator. According to safety protocols, it is generally not permitted to keep a missile loaded on the launcher rail during long marches for fear that it may be damaged, as the missile is completely unprotected. In field conditions, a missile is kept loaded on the launcher so that it can be used immediately when it is needed.
If a missile is not already loaded, the maximum rate of fire for the "Malyutka" missiles is two launches in the first two minutes when firing at the maximum range of 3,000 meters, with the first minute being largely taken up by the preparation process (40-55 seconds). After the second round is fired, the gunner must load the launcher with missiles from the reserve racks which can only be done if the turret is turned to the left or to the rear. As such, the combat rate of fire in a non-ideal situation would be less than one launch per minute. If a missile is already loaded, the gunner may be able to launch three missiles in two minutes. All four missiles may be launched in three minutes. The combat rate of fire would therefore be just over one launch per minute. At shorter distances, the flight time of the missile is correspondingly shorter so a somewhat higher overall rate of fire can be expected.
This rate of fire is nominally less than that of the 9K11 man-portable ATGM complex which can achieve a rate of fire of two rounds per minute when firing at the maximum range of 3,000 meters by having an array of prepared missiles launched consecutively, but on the other hand, the 9K11 complex requires a much longer preparation time as the ATGM team must set up multiple missiles on their individual launchers and then link them to a control unit. Case in point, a 9K11 manual states that for a three-man team with two missiles and one control unit, deploying the missile complex takes 1 minute 40 seconds. A much more unfavourable comparison would be between the BMP-1 and a self-propelled missile tank destroyer like the 9P110 which requires practically no setup time and can launch six missiles consecutively. The BMP-1 has a much slower combat rate of fire by comparison.
When resupplying the BMP-1, the missile ready racks are replenished with fresh missiles passed into the turret through the gunner's hatch.
The BMP-1 was never issued with the original 9M14 model. The improved 9M14M model was the basic variant for the BMP-1. All Malyutka-type missiles are compatible with the BMP-1's launcher system.
BMP-1P (Object 765 sp. 4)
"KONKURS" MISSILE SYSTEM
The Object 765 sp.4, better known as the BMP-1P, had its "Malyutka" missile system replaced with an externally mounted 9P135M launcher post. The joystick control box and the missile launch rail for the "Malyutka" system were removed in this modification. Older BMP models updated to the BMP-1P standard had the missile loading hatch welded in place as shown in the photo on the left below (photo by Yuri Pivkin), while new production turrets did not have a hatch fitted at all, instead having a modified roof construction as shown in the photo on the right below (photo from the militaertechnik-der-nva website).
There are some unique points about the BMP-1P's missile configuration. Firstly, the missile launcher is placed on the turret roof so it was still possible to assume a turret-down position when using the ATGM.
The main drawback was the inability to fire missiles from under armour. Besides eliminating its ability to fire a missile in an NBC-contaminated environment, it also became much easier for enemy forces to suppress the BMP with indiscriminate fire if its approximate location is detected. It is worth noting that with the hatch locked in the open position and the gunner's eye placed on the 9P135M launcher eyepiece, the gunner is almost completely shielded by the hatch and only a small part of his head can be seen from the front. In this regard, the operator can be considered well protected, but only from machine gun fire and the fragments of tank shells falling short in front of the BMP. It was not safe for him to operate the ATGM under artillery fire.
Unlike the "Malyutka" system, it was permitted to keep the launcher loaded with a missile during non-combat operations as the missile is housed in a protective fiberglass container. Nevertheless, it was usually stowed inside the vehicle when it was not needed.
The main drawback was the inability to fire missiles from under armour. Besides eliminating its ability to fire a missile in an NBC-contaminated environment, it also became much easier for enemy forces to suppress the BMP with indiscriminate fire if its approximate location is detected. It is worth noting that with the hatch locked in the open position and the gunner's eye placed on the 9P135M launcher eyepiece, the gunner is almost completely shielded by the hatch and only a small part of his head can be seen from the front. In this regard, the operator can be considered well protected, but only from machine gun fire and the fragments of tank shells falling short in front of the BMP. It was not safe for him to operate the ATGM under artillery fire.
Regardless, there are certain advantages. For example, the gunner's view is obviously much improved outside the turret, so it is easier to find targets by eye. The placement of the launcher above the turret roof also presents certain tactical advantages. The vehicle can be parked behind a pile of rubble, a hill, a mound, a wall, or even just a particularly large bush, and it will be possible to hide the entire silhouette and still use the vehicle's missile launcher. Still, these advantages are purely circumstantial. It would still be much better to have an under-armour missile launching capability, and preferably the ability to reload under armour too.
The situation with the BMP-1P is not so different than its contemporaries like the Marder 1. The Marder 1 did not even have an ATGM launching capability until it was modernized in 1977, and the upgrade only involved installing a simple launcher post beside the commander's hatch, identical in form and function to the one on the BMP-1P. Also, it should also be pointed out that only one Marder in a platoon of three vehicles was given this modification with a MILAN launching unit and the missiles to use with it. This was purely for doctrinal reasons. The Marder's turret has a two-man crew and it is the commander who operates the ATGM, so the gunner is ostensibly free to carry out other tasks unlike in a BMP-1P, but technical limitations limit the gunner of a Marder in his abilities to contribute. While the commander is operating the ATGM system, the turret is locked in place and the autocannon is disabled. The AMX-10P faces a similar conundrum. Clearly, the simplistic implementation of anti-tank missiles on most of the modern IFVs of the time was a global trend that the BMP-1P simply followed. It is no better or worse than its contemporaries in this regard.
AIR DEFENCE
It is also worth noting that as a general rule, low-pressure cannons are completely ineffective against low-flying aircraft, including helicopters, if they only fire conventional ammunition with conventional fuzing systems. However, this was largely ameliorated by the inclusion of the 9K32 "Strela-2" MANPADS system with two 9M32 missiles in the combat load of a standard BMP-1 for one of the passengers to use from one of the roof hatches of the passenger compartment or while dismounted. This system entered service in 1968 and was issued to BMP. In 1970, the 9K32M "Strela-2M" system entered service. It had improved performance characteristics compared to its predecessor and featured the ability to engage jet aircraft in a head-on attack, whereas the "Strela-2" was limited to tail chase attacks only. Newer systems such as the 9K34 "Strela-3" began to be issued in the mid to late 1970's, while the 9K310 "Igla-1" and 9K38 "Igla" became available in the early 1980's.
Officially, the 9K32 "Strela-2" was specified for the BMP-1 (Object 765 sp.2), while the 9K32 "Strela-2M" was specified for the BMP-1P (Object 765 sp.4). Only the BMP-2 was officially specified to have the 9K34 "Strela-3" system. However, due to the fact that the MANPADS issued to the vehicles are self-contained systems that are used by the passengers, there was no strict policy on their distribution other than the priority of the motorized infantry units. In practice, even the oldest BMP variants could enjoy the enhanced air defence capabilities provided by the latest MANPADS models if sufficient quantities were issued to replace older models. For example, the photo below shows an "Igla" being used by a passenger in a basic BMP-1. This would be an impossible combination if the specifications were strictly followed.
Two 9M32 or 9M32M missiles with a single launcher could be carried in each BMP. One missile was stowed on top of the central fuel tank with clips while the other missile was stowed on the left hull wall with clips. If the space on top of the central fuel tank was not used for a missile, it could be used to stow an additional RPG-7 grenade launcher. The location of the two missiles is shown in the drawing below. They are marked in red and labeled (15) and (20).
The short clip below shows a MANPADS being fired from a moving BMP-1.
In the book "Soviet/Russian Armor and Artillery Design Practices: 1945-1995" by the Marine Corps Intelligence Activity and in the book "BMP Infantry Fighting Vehicle 1967–94" by Steven J. Zaloga, it is reported that initially, one missile and one launch unit was issued per two vehicles. The exact timeframe was not specified. Later, each vehicle was issued with one launch unit and two missiles, thus quadrupling the number of missiles available in each BMP-equipped motorized infantry unit. With such a high concentration of anti-aircraft weapons, the ability of each unit to defend itself from air attack is highly noteworthy. This was a valuable capability for the Soviet Army given that the Soviet Air Force was not expected to be capable of maintaining air superiority except in some localized areas.
Despite its inherent limitations, this type of air defense system could be considered to be a more effective alternative to the rapid-fire autocannons of foreign IFVs against both modern jet-propelled aircraft and helicopters. Against fixed wing jet aircraft, the probability of kill depends on a number of factors including the number of engines; twin-engine aircraft have a high chance of surviving a hit from a MANPADS missile as it would most likely hit one of its engines, leaving the other engine intact. The overall probability of kill against a jet fighter with the "Strela-2" is stated to be 19-25% in the article "Переносный Зенитные Ракетные Комплексы "Стрела-2" и "Стрела-3"" (Man-portable Air Defense Missile Systems) published in the May 1999 issue of the "Техника и вооружение" magazine. The probability of kill of the "Strela-2M" against the same target was 22-25%, and for the "Strela-3" it was 31-33%. The all-new "Igla" series had greatly enhanced performance, with the "Igla-1" achieving a probability of kill of 44-59% against a jet fighter while the "Igla" could achieve a probability of kill of 45-63% against the same target. These figures are repeated in the book "Зенитные ракетные комплексы" (Anti-Aircraft Missile Complexes) by Nikolai Vasilii and Aleksandr Gurinovich.
Given that two missiles were carried in each BMP, there can be two attempts with an overall probability of hit of 19-25% each, so the theoretical probability of achieving one aircraft kill per BMP using the "Strela-2" can be considered to be 34.9-39.2%, and if the "Strela-3" system was used instead, the probability of one aircraft kill per BMP increases to 52.4-55.1%. Using the newer "Igla-1", the probability of one kill with two missiles increases to 68.6-83.2%. With the much more modern "Igla" the probability of one kill with two missiles increases to 70-86.3%, and indeed, the likelihood of downing one aircraft with a single "Igla" missile is already high enough that two attempts may not be needed.
To achieve a similar probability of hit with a 20mm autocannon aimed with conventional optical sights, hundreds or even thousands of rounds would be required. Indeed, the primary incentive of developing man-portable air defense missile systems during the 1950's and 1960's was the very low efficiency of conventional guns against jet aircraft which were too fast for a human gunner to engage without computer assistance. For example, on page 20 of the book "Self-Propelled Anti-Aircraft Guns of the Soviet Union" by Mike Guardia, it is stated that a M163 VADS firing a 60-round burst at a MiG-21 in level flight from a range of 1 km with its 20mm M61 Vulcan cannon had a kill-per-burst probability of just 0.08, or 8%. To achieve a probability of kill matching the "Strela-2", six 60-round bursts would be required, expending a total of 360 rounds. To achieve a probability of kill matching the "Strela-3", ten 60-round bursts would be required, expending a total of 600 rounds.
It is important to note that the M163 VADS fire control system included a radar rangefinder and an automatic target lead computer, and the M61 Vulcan cannon installed in the M163 had a high rate of fire of 3,000 rounds per minute. To put this in perspective, a Marder 1 IFV had a 20mm MK.20 Rh 202 autocannon that fired at less than a third of the rate of the M61 Vulcan on the M163. The Marder 1 itself had no optical or laser rangefinder, no firing solution calculator, and it had only simple lead markings in its optical anti-aircraft sight. It was the same for the AMX-10P. These IFVs would probably have to expend their entire ready supply of 20mm ammunition simply to guarantee at least one hit on a fixed-wing aircraft, and to achieve a 50% kill probability may require the expenditure of their entire ammunition supply.
Moreover, the maximum range of the "Strela-2" was 3.4 km and its maximum altitude was 1.5 km while the "Strela-2M" had an even longer range of 4.3 km and higher maximum altitude of 2.3 km, which is more than double the maximum effective range and altitude of the 20mm MK.20 Rh202 and HS.820 autocannons against air targets. The larger 25mm M242 chain gun of the M2 Bradley had a longer range than these 20mm autocannons, but it was considered to be only suitable for suppressive fire against helicopters at a maximum range of 2,500 meters while FM 3-22.1 (Bradley gunnery field manual) states that too many rounds are required to achieve a kill when firing at air targets beyond 1,700 meters. The 30mm RARDEN autocannon of the FV510 Warrior had a longer range, but the FV510 itself was wholly inadequate against aircraft of all types due to a combination of the extremely low rate of fire of the RARDEN and the severely limited speed of its hand-cranked gun laying system.
 |
| Two "Strela-2M" missiles fired simultaneously from separate vehicles |
The sole advantage held by IFVs with fast-firing 20mm autocannons is their ability to react more quickly to the sudden appearance of enemy aircraft flying at a low altitude. These may be fixed wing aircraft or helicopter gunships. Fighter-bombers attacking with bombs are a viable target, but ground attack aircraft flying missions against armoured vehicles were almost always armed with rockets. Helicopter gunships were universally armed with rockets for such missions, occasionally supplemented with ATGM systems. Unguided rocket systems like the Hydra 70 and S-8 were typically used from a range of up to 2.0 kilometers against point targets and airborne ATGM systems generally had a range of 3.0 kilometers or longer. With a maximum effective range of 1.5 km against aircraft, 20mm autocannons do not offer any standoff distance against such threats.
The ideal air defence system is a combination of a fast-firing autocannon of a larger caliber with a MANPAD system operated by a passenger - this was later achieved with the BMP-2 which featured a 30mm autocannon with a range of 3.0 km against air targets and a 9K34 "Strela-3" system with a range of 4.1 km or a 9K310 "Igla-1" system with a range of 5.2 km. Such a combination allows two targets to be engaged simultaneously, or for one target to be engaged by both types of weapons for a higher probability of kill.
All in all, it can be said that the BMP was not inferior to later foreign IFVs with 20mm autocannons like the AMX-10P and Marder 1, and it could even be considered to be outright superior to much newer IFVs like the M2 Bradley and FV510 Warrior. Only the BMP-2 surpassed the BMP-1 in this regard.
Besides engaging aircraft with a MANPADS system, it was also possible for the passengers to fire their small arms from the roof hatches at aircraft flying overhead. It would not have been effective, of course, but it was the only option for the passengers of a BMP that was not issued with a MANPADS system.
SMOKESCREENING SYSTEM
902V "Tucha"
The 902V "Tucha" smokescreening system was a standard feature of the BMP-1P (Object 765 sp.4) and was retrofitted to older BMP models at an unknown rate. Although it appears to be a straightforward modification, the addition of the "Tucha" system involves more work than the installation of the external missile launcher on the BMP-1P since the grenade launching system connects to the vehicle's electrical system and has its own control box. This means that the old master control panel used to power up ancillary systems had to be replaced with an updated one.
A bank of six 81mm smoke grenade launchers are arranged around the rear of the turret, aimed directly forward. The gunner aimed the grenades using the 1PN22M1 or 1PN22M2 sight. The grenades had to be aimed because they do not produce instantaneous smokescreens for self-concealment but are instead propelled to a range of 200 to 350 meters after launch and emit smoke after landing.
A more detailed examination of 3D6 and 3D17 smoke grenades is available in this page. During the career of the BMP-1 in the Soviet Army, the 3D6 was the only smoke grenade type issued.
PASSENGER SPACE
Each passenger was provided an internal space of 0.54 cubic meters. The seating positions of the passengers were designed to accommodate average Soviet adult men of a fighting age, but the percentile requirement for the passengers is not known. In terms of real volume, the BMP-1 was marginally superior to the M113 which provided each of its passengers with an internal space of 0.51 cubic meters. However, the relative volume of the BMP-1 was greater than the real volume suggests due to the considerable anthropomorphic differences between Soviet and American men in the 1960's.
To fully appreciate this difference, it is necessary to understand that the 95th percentile American ground forces serviceman had a weight of 91.5 kg based on measurements in 1966 and in 1977 with large sample sizes of USMC and U.S Army personnel, whereas the 95th percentile Soviet young adult male (conscription age) had a weight of 81.57 kg according to the USSR Anthropometric Atlas, 1977. Moreover, Soviet young adult males who reach conscription age in the 1960's should be significantly lighter than their juniors in 1977 due to food shortages during their childhood in the 1940's. Naturally, the dimensions of Soviet men were also smaller than their American counterparts including in critical points such as stature, shoulder width, and leg length, all of which are used as guidelines when allocating space for the passengers in a vehicle.
The significantly smaller bulk and dimensions of young adult Soviet males during the 1960's made the modest internal space of the BMP-1 more comfortable for its passengers relative to the M113, although it was still not luxurious by any standard.
In the U.S, tests of a captured Syrian BMP-1 trophy from the 1973 Yom Kippur war found that the ergonomics of the passenger compartment met the minimum human engineering standards used by the U.S Army. The BMP-1 was deemed to be acceptable for accommodating only 30th percentile American men, whereas the M2 Bradley was designed to accommodate 95th percentile soldiers under the same standards, using ANSUR (U.S. Army Anthropometric Survey) data from the 1970's. Height was given the most attention in the passenger compartment design, but the seating space was still extremely tight in terms of length and width, especially if the passengers wore their standard PASGT gear.
Similarly, if the passengers in a BMP-1 wore a 6B2 or 6B3 vest as issued in the 1980's, it becomes excessively cramped for comfort over long periods. However, with all this in mind, it should be clear that the space allocated for the passengers in the BMP-1 was adequate for the demographic it was designed for, and it was on par with comparable personnel carriers from the same period. Since the 1960's, the average height of Russian men has increased quite noticeably such that the average heights of Russian men have equalized with other developed nations. Because of this, it is not surprising that the BMP-1 is considered very cramped by today's standards, especially considering that bulky body armour is normal equipment for soldiers today. This already became a noticeable issue in the 1980's, when body armour became commonplace for Soviet Army soldiers in Afghanistan.
The passengers in a BMP exit through a pair of rear doors. The port side rear door holds 55 liters and the starboard side door holds 67 liters. The port side door has a smaller capacity as it has a firing port built into it.
Although powered exit ramps were favoured over doors in the West, a pair of doors allowed passengers to dismount quicker compared to a powered ramp. For the BMP-1 specifically, a pair of doors was the most rational design decision given that the passengers were seated in two rows, separated by a divider. In the U.S, the M44 and M75 were the only APCs that allowed passenger egress through a pair of doors. They were replaced by the M59 and then the M113, both of which used a powered ramp with a single embedded door in case of a power outage or mechanical failure with the ramp. The French AMX-10P IFV combined a powered exit ramp with a pair of doors, and the Marder 1 had only a powered ramp with no door. If the powered ramp failed for any reason, the passengers in a Marder 1 would be forced to exit through the roof hatches.
In the entry on the Pbv 302 armoured personnel carrier in the official website of the Swedish Arsenalen museum and in the Pbv 302 article on the Ointres website by Rickard Lindstrom, it is stated that Swedish trials found that the passengers could dismount faster with two rear doors instead of a powered ramp like on the M113. Initially, an early prototype of the Pbv 302 had been fitted with a powered ramp inspired by the M113, but they were abandoned shortly afterward. The serial Pbv 302 had two rear doors, like the Soviet BMP and MT-LB.
Outstanding article! It was worth the wait.
ReplyDeleteYou almost make me want to write more of these :P
DeleteGreat article. Compiling this kind of information must be hard work...
ReplyDeleteThat's why I won't be doing any more of these for the foreseeable future.
DeleteAn even better upgrade would be to use the Bereg turret - essentially the same as the BMP-1-30, but with advanced sights and Kornet ATGMs.
ReplyDeleteP.S.: You should do an article on BMP-1 modernization options.
Keep up the good job.
I'm afraid that I won't be keeping up the "good job", anonymous. Reality is knocking on my door, and I have to answer it. I won't be writing for Tankograd any time soon. I will still correct errors if readers find them, though.
DeleteDespite a "Field disassembly" article, it is highly detailed and informative! Great job!
ReplyDeleteAs for the hit probability of the weapons in the hungarian army... Well, that is a shameful story. Our infantry was especially poorly trained amongst WP states. Since BMPs belonged to MRDs, the results were horrible. Gunners had little experience with the gun, and almost none with the Malyutka. One unit managed to achieve only 20% accuracy with the ATGM. Another unit cheated on the exercises: They "imported" tank destroyer crews (9P133), who were far better trained, so the unit commander avoided shame... After some scandals, training of BMP crews improved. They were now able to achieve 70+% hit probability with gun @ 500m against moving target (2x2m), and 85+% with Malyutka (range unknown). If conditions were ideal, no wind and stationary target, the hit probability was at least 95% @ 500m. The 2000 simulated shots were applied to tank destroyer crews, not for BMP, they werent even allowed to touch the real thing before this 2000 shots.
That's very interesting stuff. I must do more research!
DeleteAn absolutely fantastic article. It's quality was as good as always, the BMP-1 is a widely known vehicle but so little in detail is known to us common folk. The wait was worth it.
ReplyDeleteThanks, Nick. And thanks for the consistently positive commentary! We have a very nice little community, don't we?
DeleteA very nice community indeed.
DeleteHave you thought of getting a Patreon Account? With that, us the readers could supply you a few bucks a month to or a lot depending on our pocket book sizes for writing articles here. I would shell out a few bucks a month for your excellent articles.
ReplyDeleteThat said:
Did BMP crews use the Coax as well to determine range? I recall reading accounts of WW2 Tank Crews doing that, and I wonder did sights improve enough that that was no longer necessary, or did gunner get enough mathematics training to rapidly calculate all the variables and engage?
Hi again, Golladay. Yes, I was thinking of Patreon, too, and I have some plans to use the money to get translators and pay commissions to authors. I posted a few paragraphs on that in the 'Announcements' page. The tab for 'Announcements' is just beside the 'Home' tab.
DeleteUnfortunately, I cannot give a direct answer to your question, because I have never come across primary sources (soldiers' journals) mentioning it. As far as I know, BMP gunners preferred to conduct fire adjustment the usual way - by observing the impacts of their previous shots. It is definitely possible that some gunners used the coax as a rangefinder, but they probably did it unconsciously. In Chechnya, for instance, a BMP gunner may rake a window suspected to host an enemy sniper out of instinct. In doing so, he can know the range to the window, but it would be inadvertent.
You probably already know this, but just to be safe; coax ranging is possible in any fighting vehicle, but it is not very effective without special ranging ammo. Regular 7.62x54mm B-32 ammo has a small incendiary filling at the tip, so there's some flash when it strikes hard targets, but it's not obvious enough at long distances. This is why larger bullets, like .50 BMG, are used in ranging guns and not 7.62mm. 7.62mm flashes can be spotted at several hundred meters' distance, but at such short range, ranging may not be needed at all. As you might remember, PG-9 and PG-15 rocket grenades have a very flat trajectory at short range.
Gunners were trained to use the markings on their sights and the stadia rangefinder, but that was it.
A few comments:
ReplyDelete"Another big plus was that the BTR-60PB and BTR-70 were both armed with a high elevation 14.5mm machine gun ideal for mountainous warfare"
Actually, the turret on the BTR-60/70 also had a relatively small range of elevation, limited to only +30°. These vehicles received similar criticism to the BMP-1 in their inability to engage targets in mountainous terrain. It was not until the advent of the BTR-80, which featured a revised gun mounting, prompted by Afghan experience.
"All BMP-1s still in use today are armed with PG-15VN rockets, though it doesn't really mean much, as most modern armoured fighting vehicles are more or less immune to them."
This is something of an exaggeration; the PG-15VN is simply ineffective in the frontal aspect, against main battle tanks. Against the rear, or in some cases, sides of even modern MBTs, the PG-15 should still be adequate to penetrate the thinner armor of MBTs in these areas (unless ERA is deployed), in the same fashion as other IFVs armed with larger calibre autocannon.
Furthermore, other AFVs, including many IFVs, are still highly vulnerable to this weapon; there is no reason to assume that legacy vehicles still in widespread service, such as the M2 Bradley or CV-90, have sufficient protection in any aspect to resist PG-15 fire, to say nothing of even thinner skinned vehicles such as the Stryker / LAV III.
***
As an additional note, if you write further articles of this length, you may wish to adopt a standardized citation style (e.g APA, Chicago, MLA) for your references. I'm hardly a stickler for this in most online writing, but for a piece of this length and sophistication, adopting a standardized style could help the article flow more smoothly, and assist readers in locating sources in the future if links go dead.
Oops. That last sentence of the first paragraph should read:
Delete[prompted by Afghan experience] ...that greater elevation capacity was added.
I apologize for the mistake. You are absolutely correct on the first point. The offending statement has been removed.
DeleteOn the second point: My pessimistic assessment of the PG-15VN does not take rear shots into consideration, for obvious reasons. The sides of some MBTs may be dangerously vulnerable, certainly, (the Leopard 2 comes to mind), but this is why I did not build my statement on absolute terms. Some MBTs may be vulnerable, yes, but the majority of them are more or less immune, with emphasis on "more or less". Plus, the chances of scoring a meaningful hit drop abysmally when ERA is involved. I agree that old Bradleys and Marders are completely vulnerable to the PG-15VN, but as the modern updates of these IFVs can be given a coat of reactive armour at will, the BMP-1 is largely alone in its anachronism.
I feel the same way about the citation system. I am fully aware that it is rather amateurish in its current form, and I intend to upgrade to Harvard style referencing in future articles. Existing articles may be overhauled as well, but I can't promise anything.
I really appreciate readers with an eye for detail like you. Thanks for taking the time to read the article in its entirety and thanks for composing a very constructive comment!
Thank you a lot for this, your site is such a wonder of information.
ReplyDeleteCan someone clarify on the engine--are the designations UTD-20, 5D20, and 3TD all for the same engine? Also, does the Baz-5937 chassis (SA-8 Gecko SAM) use the same engine as BMP-1?
ReplyDeleteThey are all the based on the basic UTD-20 but modified for different applications, so all three are physically distinct from one another in some way. The UTD-20 and 5D20 are almost identical, but 5D20 has a different cooling system and different ventilation system built into the metal of the engine itself, so it is not interchangeable with the UTD-20 between the vehicles that they were designed for. 3D20 is a heavily modified variant of the UTD-20 for marine applications and is optimized for propellers and water jets and that kind of stuff, so it runs in a much narrower range of revs, has different cooling system, etc.
ReplyDeleteThe BAZ-5937 uses a modification of the 5D20 called the 5D20B-300. It's a bit more powerful (300 hp). There are other differences, of course, but only a mechanic needs to know them. I hope this is helpful to you.
What is the weight of the BMP-1 turret, loaded/unloaded?
ReplyDeletePG-15VNT tandem warhead HEAT from Bulgaria should still make BMP-1 a danger to other IFVs, and side/rear of even many modern MBTs.
ReplyDeletePossibly, but the main constraint is the archaic aiming devices. There would probably never be a situation where a standard BMP-1 will ever get the chance to fire the first shot at a modern IFV or MBT at the effective range of the "Grom".
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As of this time, June 2019, I'm hearing some plans from Russia to upgrade its stock of BMP-1s into BMP-1AMs. It seems to be a straightforward upgrade, rip off the old 73mm turret and replace it with a BPPU-1 overhead turret with 30mm 2A72, like in the BTR-82A.
ReplyDeleteThe 2A72 is familiar as it has been covered in the BMP-3 article, but the BPPU-1 itself is frustratingly under-documented. It seems to be stabilized and fitted with TKN-4 day/night sights, with no mention of thermal imaging or laser rangefinding--or antitank missiles. So, all in all, a cheap, sensible modernization. (Any further info on the BPPU-1 would be greatly appreciated, as it's been showing up as something of a "universal" light turret.)
Funnily enough, I've been working on a BTR-82A article recently. It's still far from complete so it will probably be published in a few months. But with regards to the BMP-1AM itself, I really wouldn't call it a "sensible" modernization, although it is certainly cheap. Honestly, it's rather bad in my opinion. The lack of any anti-tank capability is just one major issue out of many.
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A brilliant article, I truly enjoy these posts.
ReplyDeleteI hope in the future you can detail the Soviet-Afghan War BMP-1D modifications that seem to include applique armour and the mounting of the AGS-17 "Plamya" automatic grenade launcher in place of the ATGM system.
Yes, that could be added in the future.
DeleteThis is fantastic. Thank you.
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ReplyDeleteDo you have any info on the atgm basic load and storage of missles for the bmp-1p
ReplyDeleteIt carries four ATGMs, but exact stowage scheme is still unknown.
DeleteDoes anyone know what the designation of the standard turret and its weight is?
ReplyDelete