This drop-in .22 LR Conversion System comes completely assembled and ready to install in any AR-15 / M16. No gunsmithing or permanent alterations to your rifle are required – it uses your factory upper receiver, barrel, fire control system, buffer and spring. Installation is a simple matter of replacing the bolt and carrier with the CMMG conversion unit, closing the receivers, and loading up the included magazine with high-velocity round-nose .22 LR ammo. These kits are test fired to ensure correct function, and are precision machined from high-grade stainless steel and brass to highest standards for proper fit in any mil. spec. .223 / 5.56 mm rifle or carbine. One gray polycarbonate 25 round magazine is included which features a self-lubricating anti-tilt follower and constant-force spring to help ensure reliable feeding (additional mags available on this website). Using a .22 Conversion Kit will save you a significant amount of money on ammunition and help hone your shooting skills. Made by CMMG in the USA. Due to state regulations this kit cannot be shipped to California, District of Columbia, Colorado, Connecticut, Maryland, Massachusetts, New Jersey, New York and Hawaii. Parts of Illinois, Indiana and Ohio also have local restrictions.