Soviet T-28 and T-35 tanks catch a lot of flak for being big, heavy, and not particularly well armoured in the era where anti-tank cannons became very common. German pre-war intelligence identifies the T-28 and T-35 as vulnerable to 37 mm guns from 450 meters, and yet the 94th Anti-tank Squadron of the XXXXIX Mountain Corps had a different experience. In a report titled "experience of an anti-tank unit in the East" they write:
"In one case, we managed to impede the attack of a heavy Russian tank "T-28" (or "T-35") by disabling its turret rotation mechanism. Shooting at the front or sides of the turret with PzGr 39 and PzGr 40 shells out of 37 mm guns at a range of 250 m had no effect."
CAMD RF 500-12480-145