A revolver is a repeating handgun that has a revolving cylinder containing multiple chambers and at least one barrel for firing. Revolvers might be regarded as a subset of pistols, or as an equal-ranking subset of handguns, distinct from pistols. Though the term "revolver" usually only refers to handguns, other firearms may also have a revolving chamber. These include some models of grenade launchers, shotguns, and rifles.
Though the original name was revolving gun, the short-hand "revolver" is universally used. (Cannon using this mechanism are known as revolver cannon.) Nearly all early revolvers and many modern ones have six chambers in the cylinder, giving rise to the slang term six-shooter; however, revolvers with a number of different chambers have been made, with most modern revolvers having 5 or 6 chambers.
The revolver allows the user to fire multiple rounds without reloading. Each time 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 a single-action revolver, the user pulls the hammer back with his free hand or thumb; the trigger pull only releases the hammer. In a double-action revolver, pulling the trigger moves the hammer back, then releases it, which requires a longer and heavier trigger pull than single-action. Loading and unloading a double-action revolver requires the operator to swing out the cylinder and insert the proper ammunition, all while keeping the gun pointed in a safe direction.
The first guns with multichambered cylinders that revolved to feed one barrel were made in the late 16th century in Europe. They were expensive and rare curiosities. Not until the 19th century would revolvers become common weapons of industrial production. One of the first was a flintlock revolver patented by Elisha Collier in 1814. The first percussion revolver was made by Lenormand of Paris in 1820 and the first percussion cap revolver was invented by the Italian Francesco Antonio Broccu in 1833. He received a prize of 300 francs for his invention; although he did not patent it, his revolver was shown to King Charles Albert of Sardinia. However, in 1835 a similar handgun was patented by Samuel Colt, who would go on to make the first mass-produced revolver.