German submachine gun with cal. 9 mm, built from 1938 to 1945 for German troops in WWII, due to the high number produced used in many later conflicts

The MP-40 (German: Maschinenpistole 40) (English: Machine pistol 40), is a type of sub-machine gun. It is also known as the Schmeisser for Hugo Schmeisser, who designed other weapons but not this one. It was developed in the late 1930s and was first used in the early 1940s. It was used by the German Military during World War 2. It fired 9mm bullets and had a 32-round magazine. The weapon could only fire in full-automatic fire, but since the weapon had such a slow rate of fire of 500 rounds per minute, it was possible to fire individual bullets. It was one of the first weapons made completely out of plastic and steel, making it both cheap and quick to make. The design was so good and so reliable that British soldiers would often ditch their own Sten sub-machine guns and use the MP-40 instead. This would not have been a big problem since both weapons fire the same type of bullet and clip.

A MP-40 gun