CMMG Mk57 Rimfire AR-15 Conversion Kit with 25-Round Magazine 22 LR Stainless Steel

Please note: this kit only works with CMMG 5.7 uppers. It won't fit 223 or 5.56mm uppers. Only purchase this upper if you plan to use it in a CMMG Mk57 upper chambered in 5.7x28mm! Easily convert your CMMG 5.7x28mm Upper Receiver Group into a .22LR in seconds! The new Mk57 .22LR Conversion Kit is simple to use. Just remove the existing CMMG bolt carrier group from your 5.7A-28 upper and replace it with the drop-in conversion. Pair the upper with any Mil-Spec AR15/Mk4 lower receiver and then use