CMMG AR Conversion Kit, 22LR, Stainless Steel Bolt Group, 3 Magazines, 25Rd 22BA651 Just swap this drop in conversion with the bolt carrier group from your 5.56/.223 chambered rifle and you will be ready to shoot .22LR. Ships with Three 25rd 22LR magazines. 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.