"To the Deputy People's Commissar of Defense, Marshal of Artillery, comrade Voronov
To the Chief of GAU, Colonel-General of Artillery, comrade Yakovlev
The faculty of artillery armament at the Dzerzhinskiy Order of Lenin Academy developed a design and an experimental prototype of two types of 25 mm semiautomatic AT guns (main author of the project is Engineer-Lieutenant-Colonel comrade Sidorenko). Work began in April of 1942 but due to a lack of materials and difficulty of production in Middle Asia, was only finished in January of 1943.
The prototype is worthy of attention for the following reasons. After the project began, information about the German 28/20 mm caliber AT rifle was acquired. The designed prototype is close to this rifle in its specifications, but is significantly more powerful. A comparison of the two systems follows.
To the Chief of GAU, Colonel-General of Artillery, comrade Yakovlev
The faculty of artillery armament at the Dzerzhinskiy Order of Lenin Academy developed a design and an experimental prototype of two types of 25 mm semiautomatic AT guns (main author of the project is Engineer-Lieutenant-Colonel comrade Sidorenko). Work began in April of 1942 but due to a lack of materials and difficulty of production in Middle Asia, was only finished in January of 1943.
The prototype is worthy of attention for the following reasons. After the project began, information about the German 28/20 mm caliber AT rifle was acquired. The designed prototype is close to this rifle in its specifications, but is significantly more powerful. A comparison of the two systems follows.
| Artillery Academy | German AT rifle | |
| Caliber | 25 mm | 20 mm |
| Shell mass | 0.295 kg | 0.122 kg |
| Muzzle velocity | 1200 m/s | 1368 m/s |
| Muzzle energy | 21600 kgm | 11900 kgm |
| Propellant mass | 0.231 kg | 0.152 kg |
| Rate of fire | 16-20 RPM | 12-15 RPM |
| Horizontal range | 60 degrees | 70 degrees |
| Time to deploy | Up to 15 seconds | 25-30 seconds |
| Mass | [illegible] | [illegible] |
| Bore axis | 300 mm | 700/420 mm |
As you can see, the system will have notably superior penetration with an almost identical weight while being easier to camouflage, with a higher rate of fire (thanks to the semi-auto mechanism) and has only slightly less agility of fire.
The ballistic data is only for the regular 25 mm sell. The author proposes a special lightened shell that would easily increase the muzzle velocity to 1500 m/s with a more powerful shell than the German rifle. Experiments showed good stability of the system.
A significant part of the semi-automatic mechanisms is built with unchanged mass production parts.
The system is simple to produce and maintain. The high muzzle velocity is also reached without the need for a conical barrel, which simplifies production.
I send two samples of the gun to Moscow for trials. The author, Engineer-Lieutenant-Colonel Sidorenko, is accompanying them.
I ask for a quick order for trials.
Academy Chief, Major-General of Artillery, Sidorov."
CAMD RF 81-12038-201
A handwritten addition to the bottom of the page reads:
"Based on the provided materials, preliminary conclusions can be made:
The ballistic data is only for the regular 25 mm sell. The author proposes a special lightened shell that would easily increase the muzzle velocity to 1500 m/s with a more powerful shell than the German rifle. Experiments showed good stability of the system.
A significant part of the semi-automatic mechanisms is built with unchanged mass production parts.
The system is simple to produce and maintain. The high muzzle velocity is also reached without the need for a conical barrel, which simplifies production.
I send two samples of the gun to Moscow for trials. The author, Engineer-Lieutenant-Colonel Sidorenko, is accompanying them.
I ask for a quick order for trials.
Academy Chief, Major-General of Artillery, Sidorov."
CAMD RF 81-12038-201
A handwritten addition to the bottom of the page reads:
"Based on the provided materials, preliminary conclusions can be made:
- The system has the following tactical advantages compared to 76 mm and 45 mm guns:
- Lower weight
- Lower bore axis
- Smaller crew
- Sufficient penetration to combat medium and light tanks at a range of up to 600 meters
- Sufficient rate of fire.
- Drawbacks compared to the same guns include:
- Lower penetration, necessitating the use of 76 and 45 mm guns along with this system.
- [illegible]
Conclusions: conditional on the correction of design flaws revealed by trials (recoil, extraction, etc), the proposed system could be adopted to replace the 45 mm gun at the battalion or even infantry regiment level.
Major-General of Artillery, Samsonov
March 30th, 1943
Moscow"