The Various German State Arsenals Erma EMP 9mm Interwar is a germany-made select-fire submachine gun chambered in 9mm Luger, introduced in 1931. Primary use: military. Type: Submachine Gun Action: Select-Fire Caliber: 9mm Luger Capacity: 25 Year introduced: 1931, Germany Weight: 100 oz Overall length: 24" Status: Discontinued Military use: Yes Intended use: military