Questions about soviet artillery and other in game

[Marcello]

Do you know what part of the tank the picture features?

Hull front, as noted.

I would also be interested to know what rounds caused the various sized holes. Nice picture

152mm,122mm and 100mm, both AP and HE, and 85mm AP. US made 76mm was also fired but possibly only at the sides.

It looks more like something cluster ammo would cause.

Not really. HEAT typically leaves small diameter holes.Besides given the angles involved it would be very problematic.

BTW source is:
http://www.battlefield.ru