To achieve this goal, Petrov's team modified the S-34 naval gun for use in an armoured fighting vehicle.

A more effective high-explosive shell was also developed after the war, taking advantage of the larger 100 mm bore.

This weapon is designated 100 56 TK in Finnish Navy service and consists of a complete T-55 tank turret without the stabilizer but furnished with a manually operated ammunition lift, a chute for used cases, and gun laying apparatus allowing indirect fire directed by remote fire control.

The maximum elevation of the barrel was also increased and the turret was furnished with new aiming optics, in some cases including a thermographic camera for night use.

[3] During World War II, UOF-412 round carried the 15.6 kg (34.39 lbs) F-412 high-explosive fragmentation shell.

The anti-tank missile is encased in the 3UBK10-1 shell, which is handled, loaded, and fired exactly like a conventional tank gun round.