CMMG 22D5B6E Replacement Barrel Kit 22 LR 4.50" Threaded Black Nitride Chrome Moly Steel, Fits AR-15/MK4
Everything you need to convert your existing upper to a dedicated .22LR. Just purchase a magazine and you are ready to go. For best performance use a round style hammer as notched hammers can cause function issues and 36 grain plated nose bullets have proven to be the best choice for function.