German captured anti-tank guns 75/55 mm RAK.41 made a strong impression on the Soviet designers. In OKB-172, TsAKB Grabin, OKB-8, as well as other design bureaus, they created several experimental barrels with a conical channel. However, in the Soviet Union, not a single cannon with such a channel was adopted for service. The main reasons were the high cost of the barrels, the technical complexity of production, as well as the relatively low survivability.
The second highlight of the 75/55 mm RAK.41 was the load-bearing shield, which replaced the lower carriage - it also found application.
In the design bureau of plant No. 172 (not to be confused with OKB-172) in the 44th year, they designed the 76-mm regimental cannon M-3-1, in which the 75/55 mm RAK.41 scheme was implemented. In November 1944, field tests of the experimental M-3-1 began. In 1945, on the basis of the M-3-1, the 45-mm M-5 anti-tank gun was created. The plant assigned this index to the anti-tank gun either out of ignorance of the work of its design bureau, or in order to confuse the "vigilant enemy". M-5 index in the 1930s had a 122-mm regimental mortar, and in the 44th year, a 122-mm corps gun was tested, also designated M-5. Of course, both guns were manufactured by factory # 172.
45 mm gun M-5
However, back to the 45mm anti-tank gun. Its barrel was regular, the rifling was the same as the old 45mm anti-tank guns, with the same 16 rifling. Semi-automatic vertical wedge shutter. The main parts of the anti-tank gun were installed on the bearing shield: an upper machine with a sight and guidance mechanisms, sliding beds, torsion bar suspension with axle shafts and motorcycle disc wheels with tires 3, 75 g 19. The upper machine, which is a ball mask, was fixed in the shield when help of vertical pivots. Rotary and lifting screw mechanisms. The horizontal guidance angle was 55 °. and the vertical guidance angle is from -9 ° to + 25 °. The recoil drive is spring, the recoil brake is hydraulic, the maximum recoil length was 750 millimeters. The height of the line of fire is 570 millimeters. Shielded shield, consisted of a pair of sheets of different thickness: front - 4 mm; back - 3 mm. The mass of the system in the firing position was 493 kg.
Ammunition and ballistics of the M-5 gun completely coincided with the M-42 (the mass of the armor-piercing projectile is 1430 g, the initial speed is 870 meters per second, and so on).
The design of the 45-mm anti-tank gun M-5 had several advantages over anti-tank guns with a "classic" carriage in terms of simplicity of the device and greater compactness, greater manufacturability in production and gain in weight. However, the mass of the gun was large enough for a battalion gun. Due to the low height of the axle of the gun and the long barrel, when transporting on uneven terrain, it stuck into the ground. The growth of the armor of American-made tanks, on the one hand, and the development of recoilless guns and domestic rocket-propelled grenade launchers, on the other, deprived 45-mm anti-tank guns of prospects. M-5 was not accepted for service.
