85 mm Gun Instructions

"Instructions from the 4th Department of the Combat Training Directorate of the Armoured and Mechanized Forces of the Red Army on the specifics of using the 85 mm tank gun

February 23rd, 1944

1. The T-34 tank uses two types of 85 mm gun: D5-T-85 and S-53.
   In combat the guns are serviced by two crewmen: the gunner and the loader.
2. The differences in characteristics of the weapons are negligible. Both are meant to combat enemy armoured vehicles, suppress artillery batteries and anti-tank guns, as well as enemy personnel, at ranges of 1500-2000 meters.
3. The ammunition consists of HE and AP shells (48-55 carried). A complete round weighs approximately 16 kg.
4. Combat missions are resolved using:
1. Firepower.
2. Mobility of fire in the vertical (-5 to +25 degrees) and horizontal (360 degrees) planes.
3. Sufficient rate of fire (4 RPM).
5. Muzzle velocity:
1. AP: 793 m/s
2. HE: 783 m/s
   A neglible difference in muzzle velocity allows the use of a telescopic sight with just one grid used for both AP and HE shells.The 10T-15 sight will be phased out.
6. The point-blank range against various targets is:
1. T-6 (Tiger) tank: 2.94 m at 1000 m
2. T-V (Panther) tank: 2.91 m at 1000 m
3. T-IV (medium) tank: 2.63 m at 900 m
4. T-III (medium) tank: 2.49 m at 900 m
7. The firepower and penetration of the shell, small dispersion (horizontal and vertical mean deviation of 0.16 m at 1000 m) allow these guns to combat enemy heavy and medium tanks.
8. The high muzzle velocity, flat trajectory, and high penetration allow the following when firing from these guns:
1. Firing should be done at maximum range given conditions of observation and combat situation (1500-2000 meters).
2. The rapid flight of the shell does not allow correction by deviation, as the shell will land before the gunner can sight it. Fire correction must be performed by moving the point of aim based on observed deviation horizontally. Range correction at ranges of over 1200 m can be done on the sight, at closer ranges by moving the point of aim.
3. It is difficult for the gunner to see the shell at ranges of less than 1000-1200 m as the smoke from the shot doesn't have time to disperse. The entire crew should observe the bursts and help the gunner correct fire.
4. Firing at moving targets that are moving at 15 kph an angle of close to 90 degrees at 800-1000 meters can be done by aiming at the leading edge of the target. At speeds of 20 kph move the sight over by half the width of the target.
   If the target is moving at an angle, halve the lead distance.
9. The precision and accuracy of the 85 mm gun is one of its main combat qualities. When training in the use of the gun, attention must be focused on precise determination of firing parameters and correctly choosing the point of aim.
   The relatively low ammunition capacity and excellent qualities of the gun mean that the crew much use the ammunition rationally and effectively. Shells must be correctly selected based on the type of target.