SMG

SmG, commonly written SMG, stands for submachine gun. It is a compact, magazine-fed firearm capable of automatic or selectable-fire operation and typically chambered for pistol cartridges. Submachine guns are designed for close-quarters combat, offering controllable automatic fire in a small package suitable for infantry, vehicle crews, security forces, and special units.

Submachine guns emerged in the early 20th century as a practical bridge between pistols and larger automatic rifles. They saw widespread use during World War II, with models such as the Thompson in the United States, the MP40 in Germany, and the Sten in Britain illustrating the utility of compact automatic fire. Postwar development emphasized reliability, manufacturability, and compatibility with common pistol calibers, especially 9x19mm Parabellum. They remained standard equipment in various militaries and law enforcement agencies through the late 20th century and into the present.

Most submachine guns use relatively simple blowback or gas-operated mechanisms and fire from either a closed-bolt or open-bolt configuration, depending on the design and fire mode. Features commonly include selective-fire switches, a pistol-grip stock, a detachable magazine, and a compact overall length for ease of use in confined spaces. Calibers commonly include 9x19mm Parabellum, with some models chambered for .45 ACP or 7.62x25mm Tokarev.

Today SMGs are largely supplanted in many front-line roles by more modern personal defense weapons but remain in use by some police special units, border guards, and select military forces. Notable examples include the Thompson, MP40, Sten, Uzi, MAC-10, and MP5.