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 25rd 22LR magazine.  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.

Features:
All Stainless Steel Construction
includes Anti-Jam Charging Handle, Cleaning Jag Guide Rod, Forward Assist Adaptor, and a 25rd Magazine.
Works in most 5.56/.223 chambered rifles.