CMMG BBL AND BCG KIT 16.1″ 5.7X28MM

The CMMG 16.1″ 5.7x28mm Barrel and BCG Kit delivers the core components needed to build an AR pistol or SBR in 5.7x28mm, utilizing CMMG’s patented Radial Delayed Blowback operating system. This system distinguishes itself from conventional direct blowback designs by reducing BCG weight while simultaneously lowering felt recoil compared to straight blowback operation, all while maintaining critical features such as last round bolt hold open. The barrel and bolt assembly integrate into a Mk4/mil-spec AR15 upper receiver and are compatible with either a CMMG Mk57 lower receiver or a Mk4/AR15 mil-spec lower receiver when paired with CMMG 5.7 AR Conversion Magazines.