Submachine gun

A submachine gun is a firearm that combines the automatic fire of a machine gun with the cartridge of a pistol, and is usually between the two in weight and size. They were first experimented with in the form of a stocked pistol being converted from semi to fully automatic in the early 20th century.

The first dedicated designs were developed in the latter stages of World War I both as improvement on earlier stocked pistols, and to offer an advantage in trench warfare. They rose to prominence as a frontline and commando weapon during World War II, and are now widely used by police and paramilitary organizations. They are ideal for close-range combat in enclosed urban environments, where a weapon's range and accuracy is less important than the ability to easily and instinctively obtain multiple strikes on a target. Pistol rounds are ideal for many law enforcement applications where innocent people are present, since they are less likely to over-penetrate and hit unintended targets compared to rifle cartridges. Conversely, they are largely ineffective against body armor, which limits modern military applications. Submachine guns lack long-range power and accuracy compared to higher power rifles, limiting their use in the open. They were also popularized in the 1920s and '30s as weapon of choice of American gangsters and police, in the form of the famous Thompson submachine gun, commonly referred to as the "Tommy Gun". Stocked automatic weapons firing pistol rounds were developed around the same time during World War I, by Italy, Germany, and the United States.