Fun fact - if the KV-2 (this tank) would fire while on an angle (on the way up a hill maybe) the turret would be torn off by the recoil.

6" in point of fact. 152mm.

The Soviets made some really impressive self-propelled guns toward the end of WW2. That cannon is an 8" howitzer. It can't run fast, but these guys weren't known for running in a fight!