In 1935, Erich von Manstein of the German Army General Staff, in a letter to General Ludwig Beck, described the idea of building assault artillery to support attacking infantry units. Five prototypes of the "zero" series were manufactured in 1937. Early modifications from Ausf.A to Ausf.F/8 were produced until December 1942.
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%.