The MP 38 and MP 40 (MP designates Maschinenpistole.), often wrongly called Schmeisser were submachine guns developed in Nazi Germany and used extensively by Fallschirmjäger, tank crews, platoon and squad leaders, and other troops during World War II.
The MP 40 descended from its predecessor, the MP 38, which was in turn based on the MP 36, a prototype made of machined steel. The MP 36 was developed independently by Erma Werke's Berthold Geipel with funding from the German Army. It took design elements from Heinrich Vollmer's VPM 1930 and EMP. Vollmer then worked on Berthold Geipel's MP 36 and in 1938 submitted a prototype to answer a request from the German Armament services for a new submachine gun, which was adopted as MP 38. The MP 38 was a simplification of the MP 36, and the MP 40 was a further simplification of the MP 38, with certain cost-saving alterations, notably in the more extensive use of stamped steel rather than machined parts.
In Project Reality, the MP40 is a submachine gun used by the Wehrmacht in Project Reality: Normandy.