Cylinder (firearms)

In firearms, the cylinder is the cylindrical, rotating part of a revolver containing multiple chambers. The cylinder revolves around a central axis in the revolver to bring each individual chamber into alignment with the barrel for firing. Each time the gun is cocked, the cylinder indexes by one chamber (in six-shooters, 60°).

Cylinders typically hold six cartridges (hence revolvers sometimes being referred to as "six-shooters"), but some small frame revolvers only hold 5 cartridges, due to the smaller overall size of the gun and reduced space availability. The Nagant M1895 revolver has a 7 shot cylinder, the Webley-Fosbery Automatic Revolver has an 8-shot cylinder in .38 caliber, and the LeMat Revolver has a 9 shot cylinder. Several models of .22 rimfire caliber revolvers have cylinders holding 9 or 10 rounds.

As a general rule, cylinders are not designed to be detached from the firearm (except for cleaning). Rapid reloading is instead facilitated by the use of a speedloader or moon clip, although these only work on break-top and swing-out cylinder revolvers, for obvious reasons.

The first generation of cartridge revolvers were converted caplock designs. In many of these (especially those that were converted long after manufacture), the pin on which the cylinder revolved was removed, and the cylinder taken from the gun for loading. Later models used a loading gate at the rear of the cylinder that allowed one cartridge at a time to be accessed for loading, while a rod under the barrel could be pressed rearward to eject the fired case. Most revolvers using this method of loading are single action revolvers.

Oddly, the loading gate on the original Colt designs (and copied by nearly all single action revolvers since) is on the right side, which may favor left-handed users; with the revolver held in the proper grip for shooting in the left hand, the cartridges can easily be ejected and loaded with the right. This was done because these pistols were intended for use with cavalry, and it was intended that the revolver and the reins would be held in the left hand while the right hand was free to load the cartridges.

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