Taurus .357 Magnum trigger

A handgun is a firearm designed to have the potential to be held and operated by one hand, although not necessarily used that way. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns (which are mounted against the shoulder).

Major handgun subtypes are the revolver and pistol; other subtypes include derringers, single-shot pistols, semi-automatic pistols, pepperboxes, and machine pistols.

The overlapping variations in meaning of the words "pistol" and "handgun" are discussed below.

Although handgun use often includes bracing with a second hand, the essential distinguishing characteristic of a handgun is its facility for one-handed operation.

A revolver is a repeating firearm that has a cylinder containing multiple chambers and at least one barrel for firing. The first true revolver — a flintlock — was made by Elisha Collier in 1818. The percussion cap revolver was invented by Samuel Colt in 1836. This weapon became known as the Colt Paterson. The first cartridge revolvers were produced around 1856 by Smith and Wesson. The original name was "revolving gun"; the short-form "revolver" is universally used.

As the user cocks the hammer, the cylinder revolves to align the next chamber and round with the hammer and barrel, which gives this type of firearm its name. The hammer-cocking happens either directly (via the shooter pulling it back) or indirectly (via the first portion of the trigger pull in double-action revolvers.) In modern revolvers, the revolving cylinder typically chambers five or six rounds, but some models hold 10 rounds or more. Revolvers are most often handguns, but other weapons may also have a revolving chamber. These include some models of grenade launchers, shotguns, and some rifles.

Revolvers have been largely replaced by semi-automatic pistols in military and law enforcement applications. Their lower ammunition capacities and relatively longer reload times compared to autoloading pistols are the main reasons for the switchover, which occurred over the first half of the 20th century for military applications, and in the 1980s and 1990s for police forces. Additionally, the flat profile of semi-automatics make them more suitable for concealed carry. Revolvers still remain popular in the role of back-up and off-duty guns among American law enforcement officers and security guards. Also, revolvers are still common in the American private sector as defensive and sporting/hunting firearms. Famous police and military revolvers include the Webley, the Colt Single Action Army, the Smith & Wesson Model 29, the Smith & Wesson Model 10, the Smith & Wesson 1917 and the Nagant M1895.