How does a sten gun work?

Answer 1

The Sten submachine gun operates by "blowback" cycling, a common method of operation used by many firearms, including many low-powered rifles and pistols. The reciever, a metal tube which retains the operating components, contains a metal cylinder called the bolt, a powerful operating spring, and the sear, a hardened hook which controls the bolt. When ready for firing, the sear holds the bolt in a retracted position with the operating spring compressed. When the trigger is pulled, the sear releases the bolt, and the spring propels it forward at high speed, where it "feeds" a cartridge from the magazine and into the firing chamber. The cartridge stops when it is fully chambered, and the firing pin, protruding from the front of the bolt, strikes the cartridge primer, igniting it and "firing" the cartridge. The cartridge casing, now empty, is thrust backward by the pressure in the chamber, propelling itself and the bolt rearward. The empty casing is ejected from a port in the side of the receiver, and the rearward movement of the bolt is halted by compression of the operating spring,which,again, propels the bolt forward to repeat the cycle. If the trigger is released, the sear catches and holds the bolt in the retracted position, halting the firing sequence. The Sten gun fires at a rate of nine shots per second(550 rounds per minute), or, a thirty-round magazine load in 3.3 seconds. The mode of retaining the bolt retracted when not firing is known as "open bolt" operation,which is both easier to engineer, and also utilized for safety reasons. The chamber of automatic weapons can easily become superheated from prolonged firing, and a cartridge stored in the chamber can be spontaneously ignited by this heat, causing what is called a "cook-off". Open bolt mode keeps the chamber empty, and also exposes the chamber to open air to facilitate cooling. For these reasons, nearly all submachine guns are "open bolt" designs.