The vehicle was developed at the beginning of the 1930s by the Design Bureau of the Kirov Experimental Machine Building Plant No. 185 (Leningrad). The project based on the T-26 light tank was designed for supporting mechanized units. Three prototypes with 76, 122, and 152 mm guns were produced. The variant with the 122 mm gun saw mass production. A total of 30 vehicles were supplied to the army. The project was discontinued in 1937.
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%.