The 203mm M1931 (B-4) Howitzer was a Soviet heavy howitzer. The guns, which fired 203mm shells, had enormous firepower and were used at very short distances to blow forts to smithereens. The nickname (given by the Germans) was "Stalin's demolition hammer".
 
3D printed model on a scale of 1:56 / 28mm with a 0.05mm layer thickness that ensures preservation of the details.