tank wall breach question

I don't know about that version of tank, but if you were going to smash through something, you'd want the gun tube out of harm's way. In a modern tank, the recoil is what ejects the empty casing. If you use the tube as a punch to make a hole, you'd eject the unfired round onto the floor.

I will echo Rob. And apart from the recoil, you would not want something getting jammed in the end of the barrel or the barrel getting damaged.

May I ask why it's breaching a wall?  A wall to a building?  Great for propaganda but seriously dangerous in real life.  Easy to disable your tank.  Easy to dislodge your track.  If it's a building, very possible there's a cellar -- and you'll fall into that cellar.  Plus you'd get a pile of crap all over the top of your tank, jamming hatches and the turret traverse and the ventilation of your engine....

Stand off and let one of your fellow tanks blow the snot out of the wall with HE -- that's the sol'n.  The flame throwing KV8 was an extremely valuable weapon -- not to be randomly used like an old disposible pick up truck.

That going thru the wall stuff is pure hollywood.

Off the top of my head, I don't recall there being that many built up areas in the Finnish-Soviet border areas of conflict.  Mostly burned out and abandoned Finnish huts.