A revolver is a multishot firearm, usually a handgun, in which the rounds are held in a revolving cylinder that rotates to fire them through a single barrel.
Revolver-type weapons are part of the long development of making better multi-shot weapons. They were partly an attempt to improve on pepper-box type weapons, which used a revolving cylinder with one set of firing mechanisms, but which had multiple barrels as well. Firing through a single barrel saved the expense and weight of having the multiple barrels of the Pepper-box. Revolvers have remained popular to the present day in many areas, although they have largely been supplanted by magazine-fed semi-automatic pistols such as the Colt 1911, especially in circumstances where reload time and higher cartridge capacity is deemed important.
A revolver works by having several firing chambers arranged in a circle in a cylindrical block that are brought into alignment with the firing mechanism and barrel one at a time. A single action revolver requires the hammer to be pulled back by hand before each shot. In contrast, in a double action revolver, squeezing the trigger can pull back the hammer to cock the gun as well as serving to release the hammer. Most modern double action revolvers can also be fired in single action mode as well, which serves to improve the shooting accuracy by reducing the force required to pull the trigger. Because of the effort required to cock the hammer is part of the firing action in a double action revolver, they can generally be fired faster than a single action, but at the cost of reduced accuracy in the hands of most shooters.
Most commonly, such guns have a five- or six-shot capacity (hence the other name Six Shooter); however, some revolvers have up to a 10-shot capacity (this often depends on the caliber, though different companies produce revolvers in the same calibers with different capacities, due to other design differences), and each chamber has to be reloaded manually. This makes the procedure of reloading such a weapon slow (even with the help of such devices as speedloaders). The alternatives are a replaceable cylinder, a speedloader which can reload all chambers at once, or a moon clip that holds a full load (Or even half of one in the case of a half-moon clip) of ammunition and that is inserted along with the ammunition.