Easy to print Zis-2 anti-tank gun, 1/100 scale, will want some greebling if scaled up. Some details have been changed for looks/ printability. This file has a lot more detail than what shows up at 1/100, and the barrel is very long and skinny (and fragile).
The "legs" are flipped upside down when attached to the model, the recoil scoop bits should go downwards.
Scale by 1.56 for gaslands / hotwheels / 1/64
Scale by 1.786 for 28mm / 1/56