"To the Chair of the Committee of Defense, comrade I.V. Stalin
According to your instructions, proving grounds trials of the 76 mm ZiS-3 divisional gun designed by factory #92 were performed at the GAU ANIOP from January 15th to February 5th, 1942.
The commission which performed the trials gave the following conclusions.
According to your instructions, proving grounds trials of the 76 mm ZiS-3 divisional gun designed by factory #92 were performed at the GAU ANIOP from January 15th to February 5th, 1942.
The commission which performed the trials gave the following conclusions.
- The 76 mm ZiS-3 divisional gun produced by factory #92 has tactical-technical characteristics equal to that of the 76 mm divisional gun mod. 1939 (USV), and has some advantages:
- The divisional gun is lighter than the USV by 420 kg.
- The clearance of the ZiS-3 is 360 mm, the USV is 330 mm.
- The overall shape of the ZiS-3 is more "squat", making it easier to conceal than the USV gun.
- Shooting directly at tanks with the ZiS-3 is easier due to both aiming flywheels being on the same side.
- The ZiS-3 gun consists of fewer parts and is simpler to produce.
- The 76 mm ZiS-3 divisional gun produced by factory #92 passed trials and can be recommended as a replacement for the mod. 1939 USV gun after:
- The leak in the return mechanism is resolved.
- The recoil length is fixed at 750 mm +/- 50 mm.
- The sight carrier on the upper mount should be reinforced, same with the level and perpendicular sight rail.
The comparative characteristics of the USV and ZiS-3 are as follows:
| Ballistic parameter | ZiS-3 | USV |
Muzzle velocity | 680 m/s | |
Maximum barrel pressure | 2314 kg/cm2 | |
Shell mass | 6.23 kg | |
Propelant mass | 1.070 kg | |
Chamber volume | 1.4837 L | |
Number of rifling grooves | 32 | |
Length of rifled barrel | 2570 mm | |
Muzzle energy | 147.6 ton-meters | |
Metal use coefficient | 132 | 96 |
Maximum range | 12900 m | 13290 m |
Mass and Design Parameter | ZiS-3 | USV |
Combat weight | 1116 kg | 1536 kg |
Maximum elevation | 37 degrees | 45 degrees |
Minimum depression | -5 degrees | -5 degrees |
Horizontal range | 54 degrees | 57 degrees |
Effort on the turning flywheel | 5 kg | 5-8 kg |
Effort on the elevation flywheel | 7 kg | 5-8 kg |
Bore axis height | 900 mm | 1027 mm |
Clearance | 360 mm | 330 mm |
Maximum height of the gun shield | 1375 mm | 1580 mm |
Height of the sight | 1060 mm | 1210 mm |
In addition, the ZiS-3 gun has a significant advantage over the USV gun in respect to production and economy:
ZiS-3 | USV | |
Use of ferrous metals | 3300 kg | 4700 kg |
Use of non-ferrous metals | 30 kg | 140 kg |
Tool-hours | 650 hours | 1070 hours |
Based on the results of proving grounds trials and comparative data, I present the draft decree on the acceptance of the 76 mm ZiS-3 divisional gun designed by factory #92.
The decree was drafted in cooperation with the People's Commissariat of Defense (comrades Voronov and Yakovlev), People's Commissariat of Armament (comrade Vannikov) and factory #92 director comrade Yelyan.
I ask for your decision.
L. Beria
February 11th, 1942"