A conversion kit can help you easily extract the maximum versatility out of your AR-15 or another rifle. In the case of an AR 15, conversion kits can run the gamut from .22LR conversions which lower your operating expenses for the AR to a much lower level, while still giving adequate target and functional training capabilities. You might also find a conversion kit in the form of a complete upper receiver for the AR15, which will allow an easy transition to a different caliber, sometimes requiring only a barrel, bolt and magazine change to offer a whole different ballistic and shooter experience. Some substantially similar cartridges can be converted to without changing the bolt or the magazine, only the barrel. All types of firearms have applicable conversion kits. This will typically also include the conversion of a rimless cartridge to be used in a revolver, like a 9mm, .45ACP or 10mm, all newly popular cartridges in the revolver market. The conversion kit int his instance might only consist of full or half moon clips that simplify loading.