A machine pistol is an autoloading pistol capable of fully automatic fire. The term can also be used to describe a stockless handgun-style submachine gun. The term is a calque of Maschinenpistole, the German word for submachine guns. Machine pistols were developed during World War I and originally issued to German artillery crews who needed a self-defense weapon that is lighter than a rifle but more powerful than a standard semi-automatic pistol. This concept would eventually lead to the development of the personal defense weapon or PDW. Today, machine pistols are considered special-purpose weapons with limited utility, with their original niche being filled with either the PDW, carbines, or simply more modern semi-automatic sidearms. Contributing to their already-fringe use, without a shoulder stock and training, machine pistols can be difficult to control for all but the best shooters.
The Austrians introduced the world's first machine pistol, the Steyr Repetierpistole M1912/P16, during World War I. The Germans also experimented with machine pistols, by converting various types of semi-automatic pistols to full-auto, leading to the development of the first practical submachine guns. During World War II, machine pistol development was widely disregarded in favor of submachine gun mass-production. After the war, machine-pistol development was limited and only a handful of manufacturers would develop new designs, with varying degrees of success.
In 1896 a select-fire pistol was patented by the British inventor Hugh Gabbett-Fairfax.
During World War I, a machine pistol version of the Steyr M1912 called the Repetierpistole M1912/P16 was produced. It used a 16-round fixed magazine loaded via 8 round stripper clips, a detachable shoulder stock and a rather large exposed semi-auto/full-auto selector switch on the right side of the frame above the trigger (down = semi & up = full). It fired the 9×23mm Steyr cartridge, with a full-auto rate-of-fire of about 800 to 1,000 rounds per minute (RPM). It weighed about 2.6 pounds.