CMMG INC.MkG SERIESLOWER RECEIVER ASSEMBLY•Build a pistol caliber carbine that operates on Glock mags with this lower •Features last round hold open that utilizes a dual-pinned full machined bolt catch linkage system for consistent reliable function •Designed to work exclusively with MkG Uppers •Billet 7075-T6 aluminum •Integrated oversized Trigger guard •Flared magwell •Oversized mag catch •Accepts factory Glock 30/21 mags •NOTE: Uppers from other manufacturer’s may work but CMMG cannot guarantee function or reliability