John Garand. Moon and half-moon A moon clip is a ring-shaped or stellate piece of metal designed to hold a full cylinder of ammunition for a revolver (generally six rounds) together as a unit. Therefore, instead of loading or extracting one round at a time, a full cylinder of ammunition or spent cases can be loaded or extracted at once, speeding the loading process. A similar device known as a "half-moon clip" is semi-circular and designed to hold a half cylinder of ammunition (generally three rounds) in which case two clips are necessary to fully load the cylinder. Such devices have most often been used to chamber rimless semi-automatic pistol cartridges in a revolver, they can also be used for rimmed cartridges to allow for the faster loading and/or unloading of a revolver. See also Speedloader Belt (firearms) Glossary of firearms terms References External links How Does It Work: Clips! (Not Magazines) - Forgotten Weapons Firearm components