The MP 40 fired the 9 x 19 mm Luger/Parabellum cartridge, had a rate of fire of 500 rounds per minute with what was a fairly controllable recoil for the time.
Derived from the MP 38, the MP 40 was easier to manufacture, with a 32 round box magazine and a metal, collapsable stock. The empty weight was about 3.97 kilograms and the length was 83.3 centimeters with the stock extended. The effective range was about 100 meters and the muzzle velocity was about 366 meters per second. Because the MP 40 had the same magazine and cartridge size as the British Sten Mk II, the weapons and ammunition were interchangeable.
MP 40: Standard production version of the Maschine Pistole, produced in the highest numbers.
MP 40/II: Variant designed with a dual magazine housing to create a total of 64 rounds ready for firing at one time, the same volume of ammunition as rival Soviet SMGs such as the PPSh-41. However, this model was plagued by jams and malfunctions, especially if dirt or debris was present, and it's lack of success meant it saw little use.
The MP 40 was the successor of the MP 38, which had several problems including that it did sometimes fire without the trigger being pulled. The MP 40 was mainly made out of stamped steel and one of the common misconceptions about the MP 40 is that the its magazine is meant to be used as a foregrip, but in reality the magazine will jam if this is done. It was used extensively by German troops in all theaters that they were present. Often incorrectly called the "Schmeisser" by allied troops, the MP 40 was not actually created by Hugo Schmeisser, but originated with the Erma concern - The Schmeisser was an SMG from the First World War. The sound of the gun earned it another nickname; 'Burp Gun'.
Another misconception about the MP 40 is that it was not used initially by nearly every single German soldier. It was actually used mainly by the Waffen-SS and paratroopers. This changed later on in the war however and by the end of World War II, over 1,000,000 MP 40s were made. The change to issuing many submachine guns to the Wehrmacht was largely effected by the Soviet Union's use of submachine guns in Stalingrad. There were many different manufacturers including Erfurter Maschinenfabrik Gmbh, and Haenal Waffen-und Fahrradfabrik AG. Regardless, after entering service in 1940, the MP 40 was used in a wide variety of locations until the end of the war.
- War Machine Magazine. Partwork from Orbis Publishing. Issue 6 - Sub machine guns of World War II. Page 116