The F-34 was ready for production, but Marshal Grigory Kulik's high-handed interference with tank appropriation had made the relevant bureaucrats too fearful of being arrested to approve the better gun.

Grabin and the director of the Kharkov Locomotive Factory (KhPZ), the centre of T-34 production, conspired to produce the F-34 anyway, and began to install the gun on new tanks.

The new T-34 Model 1941 tanks, which were issued mostly to company and platoon commanders, were immensely popular with their crews.

Letters from tank units reached Stalin's State Defense Committee (GKO), which officially authorized production.

In 1943, the thick armor of the new German Tiger and Panther tanks had rendered the F-34 gun obsolete, and experiments were conducted to find a replacement.