Light Tank Destroyer

 "Approved by Deputy People's Commissar of Defense, Colonel General of Artillery, Voronov
October 17th, 1942

Tactical-technical requirements for a 45 mm anti-tank SPG

1. Purpose of the SPG

The 45 mm anti-tank SPG is designed as a weapon for tank destroyer artillery regiments and anti-tank batteries in moto-mechanized units to combat enemy tanks and infantry.

2. Requirements for the SPG

The SPG uses the traversing part of the 45 mm model 1942 "M-42" anti-tank gun. The SPG must satisfy the following requirements:

1. Muzzle velocity of 870 m/s when firing the 1.4 kg armour piercing shell.
2. Ability to use armour piercing, high explosive, and subcaliber ammunition.
3. The practical rate of fire in direct fire mode is no less than 15 RPM.
4. The elevation angle is no less than +15 degrees.
5. The depression angle is no less than -5 degrees.
6. The traverse is at least 30 degrees(15 degrees per side).
7. The rate of elevation and traverse is at least 1.5 degrees per turn of the flywheel.
8. The bore axis height is no more than 1600 mm.
9. The gun uses the AZP sight.
10. The SPG is serviced by three crewmen (including the driver). The fighting compartment contains folding chairs for two men.
11. During travel, the gun can be rigidly fixed in the horizontal and vertical plane.
12. The gun mount must allow for comfortable loading at all elevation and traverse angles.
13. The SPG can carry two PPSh SMGs.
14. The ammunition capacity is 90 rounds for the 45 mm gun and 1000 rounds for the submachine guns. The ammunition stowage must be reliable and safeguard the ammunition during travel. It must be easy to extract the ammunition from the racks to load.

3. Requirements for the chassis

Use the T-70 tank chassis. The SPG must satisfy the following requirements.

1. The top speed of the SPG in top gear on good roads is no less than 45 kph.
2. The full travel weight of the SPG is no more than 10 tons.
3. The full travel height of the SPG is no more than 2000 mm.
4. The SPG must be stable when firing on a tilt, facing uphill, and facing downhill, at all elevation and traverse angles. The SPG can fire on the move or from a standstill.
5. The maximum grade that the SPG can climb on dry soil is no less than 30 degrees.
6. The maximum fording depth is no less than 750 degrees.
7. The SPG can tilt to 25-30 degrees.
8. The fuel tank capacity must provide for a cruising range of 200-250 km. The SPG must have an oil tank sufficient to drive for a full fuel load.
9. The gun mount must be armoured. The armour of the gun mount protects the gun, crew, fuel tanks, and ammunition.
   The gun and crew are covered from the front, sides, and rear.
   Armour thickness:
1. Front: 35 mm
2. Side: 15 mm
3. Rear: 15 mm
10. The SPG's armour must provide:
1. Secure protection of the crew and gun.
2. Ability to quickly enter and exit the vehicle.
11. The rear armour of the fighting compartment must flip out.
12. The SPG must be equipped with the following communication devices:
1. 12RP radio for external communication.
2. TPU-2 for internal communication.
13. The walls of the fighting compartment must have:
1. Observation ports for observing the battlefield and terrain.
2. Ports for firing the PPSh SMG.
14. In addition to ammunition indicated in section 2 paragraph 14, the SPG must carry the following:
1. Pioneer tools: an axe, a saw, a crowbar, and a shovel.
2. Tools and parts for the gun and chassis in a special rack.
3. First aid kits and rations for the crew.

GAU Chief, Colonel General of Artillery Yakovlev"

RGASPI F.644 Op.2 D.103 L.146-147