A revolver is a repeating firearm that has a cylinder containing multiple chambers and at least one barrel for firing. 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. In modern revolvers, the revolving cylinder typically chambers 5 or 6 rounds, but some models hold 10 rounds or more. Revolvers are most often handguns, but other weapons may also have the design of a revolver. These include some models of grenade launchers, shotguns, and some rifles.