76-mm Battalion Dynamo Cannon Bpk-76 Specifications
- Years of issue -1932 – 1935
- In total, 487 units were produced.
- Caliber – 76 mm
- Weight in firing position – 180 kg
- Barrel length – 1516 mm
- The length of the threaded part – 1110 mm
- Calculation – 4 people
- Travel speed – 5 – 7 km / h
- Rate of fire – 7 rds / min
- The greatest firing range – 7000 m
- Shooting angles:
- Horizontal – 6 °
- Vertical – 17 ° + 45 °
Since 1923, development work has been carried out in the USSR to create dynamo-reactive (recoilless) guns (DRP). These works were based on the scheme of engineers L.V. Kurchevsky and S.A. Isenbeck, in which there was a conical nozzle in the breech of the gun. When fired, the projectile in the DRP, as in a conventional artillery gun, accelerated while moving along the barrel bore by the force of the pressure of the powder gases at its bottom. In this case, the gases of the expelling charge came out not only through the muzzle, but also through the breech, equipped with a nozzle, part of the barrel.The gases escaping through the breech created a thrust that balanced the recoil force. Thus, in the recoilless gun, no significant forces were applied to the carriage, and it could have a lightweight design. However, comparing favorably with classical artillery systems with a small mass, a small effect on the carriage when fired and a low cost, the recoilless guns of that time were significantly inferior to the first ones in range and firing accuracy, and had significant unmasking properties.
Intensive research led to the creation in 1930 of the first DRP-4 gun of the Kurchevsky system. In 1932, the Special Design Bureau No. 1 of the Red Army Art Administration was created under the leadership of L.V. Kurchevsky, at whose disposal the plant number 38 in the village. Podlipki (Moscow region).
At the end of 1931 L.V. Kurchevsky created his most famous weapon, which was to become the main means of direct support of the infantry in the battalion-regiment link. It was adopted by the Red Army by the Decree of the Revolutionary Military Council in August 1932 under the designation “Kurchevsky’s 76-mm battalion cannon” (BPK-76). An important advantage of this gun in comparison with conventional 7b-mm field guns was its low weight, in the combat position – only 180 kg, which was almost eight times less than the mass of the 76-mm cannon of the 1902/30 model. A crew of 4 people could conduct intense fire, easily move the BOD-76 over rough terrain on their own.
Among its shortcomings were: a small firing range, a strong sound of a shot and a powerful jet of gases that raised a cloud of dust, unmasking the gun.
The BPK-76 cannon consisted of a barrel, a light two-wheeled carriage and sighting devices. The monoblock barrel of this gun, made ribbed to improve heat transfer during firing, had a bolt with a threaded central nozzle block. The steepness of the grooves in the bore is constant. When loading, the shutter moved together with the nozzle block. Loading was carried out from the breech. The lifting mechanism is screw. The screw operated on a lever mounted on the right pivot. The swivel mechanism is also of the screw type.
The gun had a panoramic sight with a drum equipped with two scales. A tubular welded two-wheeled carriage was a lightweight tubular welded frame with a front opener and a trunk to support the barrel in a combat and stowed position. The screw funnel was located next to the opener. The combat course consisted of chained wooden wheels on a steel axle without suspension, which excluded the cannon from being towed by a car. The BPK-76 was transported by horse-drawn vehicles.
For firing the BPK-76 cannon, 76-mm unitary shots were used from three-inch guns with a shrapnel shell, a high-explosive and armor-piercing grenade, but their sleeve differed from the standard holes – in the bottom part and on the walls, from which, after ignition, powder gases flowed out. The holes in the sleeve were closed with wooden or cardboard plugs. The thickness of the cardboard for the cork was 6 mm at the side hole and 4 mm at the bottom. The projectile had a leading belt located in the bottom, which, when it moved in the barrel bore, was easily deformed. The greatest firing range of a fragmentation grenade was 7000 m. The transfer time from the traveling position to the combat position took 47 seconds.
One of the features of the gun was the ability to use it as a mortar for firing 76-mm feathered mines at a fixed angle of 45 ° at a distance of 250 to 1000 m. At the same time, the nozzle was removed from the shutter and a device in the form of a shortened sleeve with a sting was inserted into the barrel chamber. The process of loading and firing a shot was similar to firing from a conventional muzzle-loading mortar.
The 76-mm recoilless gun BPK-76 could be easily mounted on trucks and cars and even on motorcycles, which sharply increased its maneuverability on the march and in battle. On the basis of the BPK-76, a cannon for KPK boats and a self-propelled gun SU-4 were created, which was a recoilless gun installed in the back of a GAZ-AA truck. The quick-detachable pedestal, on which the gun was mounted, provided firing both from the body and from the ground.
Serial production of BPK-76 was organized at three plants: No. 7 named after Frunze (Leningrad), No. 8 named after Kalinin (settlement Podlipki, Moscow region) and Bolshevik (Leningrad). With a total order of 959 BPK-76, 487 guns were manufactured at three factories from 1932 to 1935. By November 1, 1936, 407 BPK-76 guns were in service with the Red Army. The Kurchevsky cannon was removed from service in 1939, and all work on recoilless guns was curtailed.
In the Central Museum of the Great Patriotic War, there is a Kurchevsky 76-mm battalion cannon (BPK-76) equipped with a shutter from the non-standard system of M.N. Kanadakov and V.L. Salina.