In the autumn of 1942 the Alkett company started the development of a new SPG with a 150-mm gun. To boost new vehicle production, it was planned to use the readily available components of Pz. III and Pz. IV vehicles. The SPG was made on the same chassis as the Nashorn heavy tank destroyer. A total of 714 vehicles and 150 ammunition carriers that used the same chassis were built.
Time for the successive autoreloading of each shell into the magazine.
The technical characteristics shown are for the Siege mode
Characteristics are specified for a vehicle with crew members trained to 100%.