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 3 25rd 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. **Since .223 WYLDE is NOT a mil-spec chamber, it is NOT guaranteed to fit or function with CMMG'S 22LR conversion kits**