Wednesday, 26 October 2016

ZiS-3 Trials

"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.
  1. 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:
    1. The divisional gun is lighter than the USV by 420 kg.
    2. The clearance of the ZiS-3 is 360 mm, the USV is 330 mm.
    3. The overall shape of the ZiS-3 is more "squat", making it easier to conceal than the USV gun.
    4. Shooting directly at tanks with the ZiS-3 is easier due to both aiming flywheels being on the same side.
    5. The ZiS-3 gun consists of fewer parts and is simpler to produce.
  2. 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:
    1. The leak in the return mechanism is resolved.
    2. The recoil length is fixed at 750 mm +/- 50 mm.
    3. 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"

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