During the First World War, Steyr factory also produced a select-fire version of the M.12 pistol, with enlarged magazine that held 16 rounds, detachable shoulder stock-holster, and a fire mode selector on the left side of the frame, which allowed to fire the pistol in single shots or in full automatic mode. This machine pistol was known as M.12 / P.16. The nickname "Steyr Hahn" comes from the fact that this pistol has an external hammer (Hahn in German language), as opposed to striker-fired Roth M1907 pistol.