The Soviet T-34 Medium Tank of World War 2 (1939-1945) fame became a classic combat vehicle of the period for its wartime showing and its sheer availability in numbers. Its value was such that it continued to see service well into the Cold War period (1947-1991) and influenced a slew of tank designs emerging then. Despite this, the original version held inherent shortcomings to the point that the T-34M initiative was being drawn up even as the T-34 was in full-fledged service. However, the German invasion of the Soviet Union in June of 1941 (through Operation Barbarossa) ended all hopes for this improved T-34 offshoot as production of the base T-34 proved the greater need - just five incomplete T-34M hulls were realized by the time of the project's close.
The T-34M was being developed by Soviet engineers at Lokomotiv Works , Factory No.183 at Kharkov as soon as 1941, this while Europe was already at war, and the modernized version was known internally under the project designation of "A-43". Chief changes in the M-model included a torsion bar/arm suspension system (instead of the original's Christie) for increased off-road mobility/performance, increased internal fuel stores for improved operational ranges, increased ammo storage, improved armor protection, and an all-new, roomier, three-man hexagonal-shaped turret enclosure complete with commander's cupola atop it. The running gear was revised to include a sixth road wheel to each hull side as well as a total of four track-return rollers to better manage the track-link sections. In addition to all this, a W-2-K 12-cylinder diesel-fueled powerpack of 600 horsepower output promised better efficiency and (as was hoped) reliability.
Road speeds were estimated at 60 kmh and the vehicle's combat weight reached 32 tonnes. Dimensions included a length of 5.9 meters, a width of 2.75 meters, and a height of 2.3 meters.
The tank increased the operating crew from four to five with the driver and radioman/ bow machine-gunner located in the front of the hull and the driver, gunner, and loader in the three-man turret over midships. Primary armament was to be the tank-killing 76.2mm F-34 in the turret's frontal face backed by the usual collection of supporting 7.62mm DT machine guns to combat infantry. The effective 57mm ZiS-4 anti-tank gun was also in consideration for the primary armament.
As soon as May of 1941, the T-34M was ordered into serial production so as to have combat-ready units available before the end of the year and immediately succeed the original in-service T-34 models. However, the German invasion derailed these plans and nothing more cam of the M-model project for the T-34 demand proved too great to unseat its own production.