Grenade launcher RK MM / RK BM / DR
ETC
In the USSR, research aimed at the creation of dynamo-reactive (recoilless) guns (DRP) was carried out from 1923 on the basis of the scheme of engineers L.V. Kurchevsky and S.A. Izenbek, in which, unlike previously known devices of this kind, there was a conical nozzle in the breech.
In 1916, D. P. Ryabushinsky, one of the representatives of a well-known family of Russian capitalists, tested a 70-mm recoilless gun resembling an open tube on a tripod. Kurchevsky was well acquainted with the works of Ryabushinsky and used them in the design of the DRP.
Kurchevsky created and put into production two 37-mm guns - 37-mm RK of low power (MM) and high power (BM). Their main difference is in weight - 28 kg and 32 kg, respectively, barrel length of 1220 mm and 1250 mm and better ballistics in the 37-mm RC BM.
| RC MM | RC BM | ETC | |
|---|---|---|---|
| Caliber, mm | 37 | ||
| Length, mm | 1220 | 1250 | 1270 |
| Weight, kg | 28 | 32 | 59 |
| Grenade weight, kg | 0.6 | ||
| Sighting | |||
| range | |||
| , m | 200 | 200 | 500 |
| Armor penetration, mm | 20 |
The design of both systems is the same. In the normal position, the guns were fired from a tripod - the gunner sat next to him on the ground. It was possible to shoot from the shoulder, but it was inconvenient. It was impossible to shoot while lying down. The system is non-separable, it was transferred to the battlefield manually. Both Kurchevsky guns had a design feature that distinguished them from the developments of other designers. This difference was store food. Firing was carried out with unitary cartridges with armor-piercing shells. Five cartridges were located in the overbarrel magazine, another in the barrel. Loading was muzzle-loading using a very complex mechanism, which very often failed.
In 1935, the 37 mm RC BM was modernized. The gun itself underwent only minor changes, but the tripod was replaced by a Sokolov wheeled carriage from the Maxim machine gun. Tests revealed previous design flaws - cartridge sticking, rammer failure, problems with the rag case, etc.
In 1937-1938, the gun underwent a radical modernization and received a new name “37-mm gun DR plant No 8”. The letter “K” (Kurchevsky) was removed after his arrest in 1937.
Loading was carried out from the breech, as with a conventional cannon. For this purpose, a wedge bolt was introduced. The rag case was replaced by a brass one. The barrel was mounted on the same machine gun mount, but without a shield.
The DR gun showed good armor penetration - at a distance of 500 m, 20 mm armor was penetrated at an angle of 0 to 25 degrees.
At the end of the thirties, work on dynamo-reactive guns was curtailed, the guns were removed from service and sent for melting. The main drawback of the new weapon was the low muzzle velocity of the projectile, which made it possible to fight only light armored vehicles. This drawback could be solved with the help of shaped charges, but disappointment from the low efficiency and insufficient reliability of dynamo recoilless weapons predetermined its fate.