"Tactical-technical requirements for the design of anti-tank artillery
1. The main purpose of anti-tank artillery is the escort of armoured units, combat against enemy tanks, enemy anti-tank artillery, and suppression of machinegun strongholds (nests) during an offensive with infantry or tank riders.
2. The anti-tank SPG must satisfy the following requirements:
- Minimal possible requirements, low bore axis.
- Possibility of firing from short stops without deploying trails.
- The STZ tractor is used as chassis (if possible, without conversions or additions).
- The engine can be replaced, but only with another engine that is presently in production.
- The top speed of the SPG must be within 25-30 kph.
- The maximum ground pressure can be from 0.5 to 0.7 kg/cm².
- Maximum grade is up to 30 degrees off-road.
- Cruising range must be at least 200 km
3. The I-13-52 cannon designed by NII-13 is used (if possible, without conversions or additions) as armament, with the following characteristics:
- Caliber: 57 mm
- Muzzle velocity: 920 m/s
- Maximum pressure: 3100 kg/cm²
- Ammunition from the ZIS-2
- Vertical range: from -6 to + 12 degrees
- Horizontal range: 360 degrees (desirable)
- Recoil resistance: 1800 kg
- Recoil length: 30-40 mm
- System weight (with mount) 850 kg
- Barrel length: 3145 mm
- Penetration at 30 degrees:
- 300 m: 79 mm
- 600 m: 73 mm
- Protection of the engine and transmission from a direct hit of a 45 mm tank or anti-tank gun (45-50 mm).
- Frontal protection: 30-45 mm.
- Crew protection (side shields): bulletproof, 6-8 mm.
- The breech and roof are unarmoured.
5. Ammunition stored onboard must be at least 200 rounds, protected with bulletproof armour.
6. The crew must consist of a driver, gunner, loader, and commander.
Chairman of the NKV Technical Council, E. Satel"