The project was developed by the Construction Bureau of Kharkov Komintern Locomotive Factory No. 183. The vehicle was designed to replace the T-34. The development was based on the results of examining the most modern German vehicles of that time. The mockup committee studied the materials and proposed a number of improvements. However, after the beginning of war, all work on the vehicle was discontinued.
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%.