"May 27th, 1944
To the Chief of the GBTU Tank Directorate, Major-General of the Tank Engineering Service, comrade Afonin
Report on the issue of firing from the T-34-85M tank equipped with a PT-3 mine roller
According to orders from Deputy Chief of the GBTU, Lieutenant-General of the Tank Engineering Service comrade Lebedev, the NIBT Proving Grounds installed a PT-3 mine roller on a T-34-85 tank and determined the ability of firing from the tank after the detonation of a German TM-35 mine under the roller on May 26th and 27th, 1944.
The T-34-85M tank equipped with a PT-3 mine roller travelled on a dirt road for 1.5 km. The roller was in combat position. The turret was facing forward, with the gun level. Strikes on the gun muzzle were observed when the tank crossed pits up to 300 mm deep.
The German TM-35 mine was detonated under the two inner disks of the right side of the roller. The tank turret was turned forward, the gun was level, the traverse lock and elevation lock were disengaged.
An inspection of the tank after the mine detonated revealed the following:
- The explosion destroyed the right cheek of the mine roller frame. The roller was disabled. The tank would no longer be able to move with the roller attached.
- There is a dent on the muzzle from the left side: a mark from the impact of the roller, which was thrown upward by the mine. There is also a dent on the front part of the mine roller from the gun.
- The front of the hull and turret were covered in dirt. A 1-1.5 mm layer of dirt was left inside the barrel, 150 mm in length.
- The elevation mechanism and sight were undamaged.
As a result of the trials, the following conclusions can be drawn:
- Movement of the T-34-85M tank equipped with a PT-3 mine roller with the gun forward will result in impacts on the gun barrel even when crossing relatively small pits, which can cause damage to the latter.
- An explosion of a mine underneath the roller can damage the barrel of the gun by hitting it with the frame of the roller, which is propelled upwards, and also causing the fouling of the barrel with dirt.It is necessary to clear the dirt before firing, as the presence of dirt can lead to the barrel bursting and the shell exploding prematurely.
The T-34-85M equipped with the PT-3 mine roller can only use it with the turret turned backwards. Trawler tanks should be supported by fire from regular tanks that follow it.
Chief of the NIBT Proving Grounds, Major-General of the Tank Forces, Romanov
Deputy Chief of the NIBT Proving Grounds, Engineer-Lieutenant-Colonel Sych
Assistant to the Chief of the NIBT Proving Grounds and the Chief of the Scientific Testing Department, Lieutenant-Colonel Gerkevich"