A lightweight version of the T20 medium tank with the M7 elongated chassis. The vehicle was developed in the first half of 1943. Unlike the T20 tank, the T21 featured reduced armor and lighter armament. The vehicle never entered mass production nor saw service.
Time for the successive autoreloading of each shell into the magazine.
The improved system allows the time to be decreased for autoreloading the next shell upon firing the loaded shell when the corresponding indicator is displayed
Characteristics are specified for Siege mode.
The technical characteristics are displayed for the charged turbine 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%.