A machine pistol is a handgun that is capable of fully automatic fire, including stockless handgun-style submachine guns.[1]
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. 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.