"February 5th, 1945
Evaluation of tank armament
In 1944 the Germans accepted the Tiger B tank into service, which is now the main type of enemy heavy tank.
The Tiger B tank has powerful front armour and the 88 mm KWK-43 gun. The AP round of this gun has a muzzle velocity of 1000 m/s with an aimed rate of fire of about 6 RPM.
The second type of main German tank is the Panther medium tank. This tank has a 75 mm gun with a muzzle velocity of 1000 m/s and rate of fire of 7-8 RPM.
The AP shells of these tanks can penetrate our tanks from 1500-2000 meters.
The 76 mm M-1 gun of the American M4-A2 medium tank has a muzzle velocity of 800 m/s and penetrates 80 mm of armour at a range of 2000 meters.
The Red Army's main tank is the T-34 tank. This tank has the 85 mm ZIS-S-53 gun as the main armament that penetrates the Panther's side armour at any range and the Tiger B's side armour at 1200 m. The ZIS-S-53 gun does not penetrate the front armour of the Tiger B or Panther tank.*
The D-25 tank gun used in IS tanks surpasses all known foreign tank guns in penetration power and falls short only in the aimed rate of fire. The D-25 gun can effectively combat German tanks at any range.
The above shows that only the IS-122 tank has an advantage in armament. The T-34 tank has inferior armament to that of American and German medium tanks.
Note that the enemy 88 mm and 75 mm guns can defeat our tanks' armour (including the front armour) at 2000 meters while the 85 mm gun of the T-34 tank can penetrate only the side and rear of the Tiger B at 1200 meters and the front of the Tiger B from 700 meters.*
Proposed measures
In order to improve tank armament to allow it to penetrate the armour of modern enemy tanks, do the following:
- Develop and introduce T-44 tanks with the 100 mm D-10T gun. The due date should be established as February 15th, 1945.
- Set up production of T-44 tanks with 100 mm guns at factory #112 with the goal of transitioning fully to T-44 tanks by June 1st, 1945.
- Set up SU-100 production at factory #174 with the goal of transitioning entirely to SU-100 production by March 1945.
- Inform the NKV and GAU that all tanks and SPGs with the 100 mm gun must have the TSh-19 sight.
- To improve the rate of fire, expedite development of an automatic loader for the D-25 gun with the aim of installing it on all IS tanks and ISU-122S SPGs by April 1st of this year.
- Inform the NKV and GAU of the need to improve quality of 85 mm ammunition so that it can penetrate the side of German heavy tanks from 2000 meters.
- Instruct the NKV and GAU to develop a high caliber machine gun for heavy tanks instead of the coaxial DT machine gun.
- Instruct the NKV and GAU to install belt-fed GVG machine guns in T-34 tanks instead of DT machine guns.
- Instruct the NKV and GAU to expedite development of an 85 mm gun for light SPGs to replace the 76 mm ZIS-3 gun.
Raise the issue of producing the SU-85 at factory #40 in sync with deliveries of these 85 mm guns with the NKSM. - Raise the issue of producing at least 50 SU-37 SPAAGs at factory #40 monthly depending on the results of trials with the NKSM.
- Raise the issue of expediting the development and production of the 122 mm D-30 gun for installation into tanks and SPGs starting with July of 1945.
Deputy Chief of the 3rd Department of the GBTU USA, Engineer-Colonel Ratnikov"
CAMD RF F.38 Op.11355 D.2732 L.4,5-7
Printed in Glavnoye Bronetankovoye Upravleniye Lyudi, Sobytiya, Fakty v dokumentakh, 1944-1945 p.362
* The conflicting statements about whether or not the 85 mm ZIS-S-53 can penetrate the front of a Tiger II tank are present in the original document.