CMMG Receiver Extension Nut, Mk4 - 55CA9CB

The CMMG Mk4 Receiver Extension Buffer Tube Lock Nut is a replacement part for MSR receiver extensions. This AR castle nut is built to meet military specifications to provide long-lasting and reliable quality. This buffer tube lock nut is great for repairing or building a lower receiver extension. Repair your tactical rifle with the CMMG Mk4 Receiver Extension Buffer Tube Lock Nut.Features: Built to meet mil-spec Can be used to repair AR15 or personal builds