A revolver or six-shooter (as most revolvers have a maximum capacity of six rounds) 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 1814. 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. Though 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 ten 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.