Submachine gun

Design and characteristics

Typical features include a relatively low mass and short barrel, a detachable box magazine, and a simple operating system such as straight blowback. Many designs fire from an open bolt to aid cooling and simplify the mechanism, though some use closed-bolt firing for greater accuracy in single shots. Rate of fire, ergonomics, and accessory compatibility (sights, rails, suppressors) vary between models.

• Calibres: Common pistol cartridges like 9×19mm, .45 ACP, and 7.62×25mm.
• Operation: Blowback or delayed blowback; open- or closed-bolt designs.
• Controls: Safety, fire-selector for semi/auto, and detachable magazines.

History and development

Early experiments with compact automatic weapons appeared in the early 20th century, and the first widely recognized submachine designs emerged around World War I and the interwar period. Notable early examples influenced later mass-produced models that saw extensive use in World War II and beyond. Postwar innovations produced lighter, simpler, and more reliable weapons suitable for military, police, and security forces.

Uses and examples

Submachine guns are favored for close-quarters battle (CQB), vehicle crews, bodyguards, and law-enforcement units because their lower-powered ammunition produces less recoil and often reduced wear on structures. They remain common in policing and counter-terrorism units where rapid, controllable automatic fire is necessary at short ranges. Examples of roles and users include military special forces, internal security forces, and urban patrol teams. For general information see firearm and detailed cartridge descriptions at pistol cartridges.

Distinctions and notable facts

Submachine guns differ from machine guns in scale and ammunition, and from assault rifles by caliber and effective range. They are also distinct from the smaller, often handgun-like machine pistols and from the more recent category of personal defense weapons (PDWs) that bridge pistol and rifle characteristics. Law-enforcement adoption and military use vary by region; many police forces continue to equip teams with submachine guns for tactical operations and counterterrorism responses, as referenced by policing resources at police.