Ever wondered how a submachine gun works? The British Sten gun from 1942 is a good example of a typical submachine gun. Its called “sub” machine gun because it uses low powered pistol ammunition instead of full power rifle cartridges. It operates with a blow-back bolt, which means that the bolt is not locked but seals the chamber due to its forward inertia. This makes it very simple, but also prone to misfiring. A brilliant example of rough industrial design where function and ease of manufacture trumped aesthetics and tradition.