In May of 1941, the Council of People's Commissars ordered an improvement programme for the T-34, with an aim towards manufacturing 500 of the improved type out of the total 2,800 scheduled for production during 1941.
Besides replacing the Christie suspension with the torsion bar system, the directive also called for an increase in the frontal armor from 45mm to 60mm, the side armor to 40mm and the turret diameter to 1600mm. The programme also called for the addition of a commander's cupola to the turret. Morozov's design bureau labelled this new version T-34M.
The designers were generally dissatisfied with the L-ll 76.2mm gun selected for the T-34 by the G.A.B.T.U. Various weapons were considered as alternatives including the ZiS-4 57mm anti-tank gun and the old 45mm tank gun.
The KV heavy tank was being fitted with the new Grabin F-32 76.2mm gun which had better anti-armor performance due to its longer barrel. During the spring of 1940, V. Grabin of the Central Artillery Design Bureau began work on adapting the F-32 to the T-34 turret. By the end of the year his team had developed a superior gun, the F-34 which was slightly longer at 42 calibres.
Unfortunately, neither the Main Artillery Directorate (GAU) under Kulik nor the GABTU would authorize the production of the new gun without official approval. In an uncharacteristic move, Grabin and the plant director, A. Elyan, acted on their own initiative and produced the F-34 alongside the L-II
The first F-34 guns were completed in January 1941, and began to appear on some T-34s in February 1941. This variant, usually called the T-34 Model 1941, was not officially approved until the summer of 1941 - after the outbreak of the war when tank units in the field clamored for more F-34 guns and the abandonment of the less effective L-11 gun.
Fighting Armor Of World War 2 (T-34/76 Medium Tank)
by Steven Zaloga
T-34 (1941) This tank was captured by the Wehrmacht in 1941 and used for training in France. It was eventually captured by the US Army in 1944 and shipped to Aberdeen in the states.