Original production MP 18,I made by Bergmann. Identical to the Hugo Schmeisser design — the first submachine gun used in combat. The comma in "18,I" indicates first model, a German naming convention. Type: Submachine Gun Action: Blowback Caliber: 9mm Luger Capacity: 32 Year introduced: 1918, Germany Weight: 67 oz Overall length: 32.1" Status: Discontinued Military use: Yes Intended use: military