Aero Precision's M5 .308 Stripped Lower Receiver helps you build a big-bore AR from the ground up. Mil-spec dimensions and coating ensure the highest quality and correct component interface. The rear takedown pin detent hole is threaded for a 4-40 set screw; bolt catch is threaded for a screw pin (no roll pin needed); selector markings work with 45, 60, or 90 degree standard safety selectors; and there is no gap with aftermarket pistol grips. The M5 308 stripped lower has an integrated trigger guard, and includes a Nylon-tipped tensioning set screw. It is compatible with standard DPMS 308 components and magazines. This model has a black hard coat anodized finish.