Modernization of a fighting vehicle over the course of production is a normal phenomenon. This was not the case from the very beginning, but modernization rather than creation of whole new designs was the norm by the 1920s. In Soviet practice, a good example of this is the MS-1. The first and fourth series differ significantly, and even so the full plans for improving the characteristics of the tank were not realized as it had become obsolete and did not satisfy the military's requirements even with changes. The MS-1's successor, the T-26 light tank, shows a much fuller spectrum of modernization. It started out with two turrets, one with a cannon and one with a machine gun. The first major modernization took place in 1933, and the tank that was produced at the end of its production run differed considerably from the first vehicle. Similar processes were not unusual for tank building of the era.
|The first M4A2 tanks arrived in the USSR in the fall of 1942, but true mass deliveries began closer to the end of 1943. By that point the tank's armament was a bit weak.
|T-34 tank with an S-53 gun. Engineers Chasovnikov and Kazarin clearly knew about this project and were inspired by it.
|Chasovnikov was no dreamer. Rearming tanks was his specialty at TsAKB.
|A proposal to install the T-34 turret on an M4A2 chassis. The blueprint indicates that the tank uses an 85 mm gun, but the type is not specified.
|Location of ammunition.
|Artist's impression of what the M4A2 with a T-34 turret and 85 mm gun could have looked like.
|A more realistic proposal with an 85 mm S-53 gun installed in the M4A2.