Technical requirements for the 212A self-propelled gun were developed in August 1940. The Special Design Bureau No. 2 of the Leningrad Kirov Plant started development based on the KV-220. Blueprints for the vehicle were ready by February 24, 1941, but a prototype was never manufactured. By August of 1941, development was passed on to the UHMP (Ural Heavy Machinery Plant), but a prototype was never built.
Time for the successive autoreloading of each shell into the magazine.
Characteristics are specified for Siege mode.
Characteristics are specified for Rapid mode.
Reload time of the first and second guns on double-barreled vehicles.
Characteristics are specified for vehicles with crews trained to 100%.