The Aero Precision M5 .308 Stripped Lower Receiver helps you build a big-bore AR from the ground up. And unlike the multitudes of garden-variety stripped lowers out there, it actually features a number of enhancements to help you build a better rifle. Those enhancements are: 1. Threaded bolt catch roll pin allows for simple installation of the bolt catch and virtually eliminates the chance to damage the finish during installation. 2. Integrated trigger guard eliminates the possibility of breaking the trigger guard tabs and creates a more rigid platform. 3. Upper tension screw allows you to fine-tune the fit of the upper and lower using a nylon-tipped tensioning set screw inserted into the grip tang, providing a tight, slop-free fit with ANY mil-spec upper. 4. Threaded takedown pin detent recess allows you to install the takedown pin detent and spring with the use of a 4-40 set screw. No more launching detents across the room. Multi-caliber, works with AR 308 components and magazines Forged 7075-T6 aluminum construction Type III hardcoat-anodized finish Integrated trigger guard Selector markings will work with 45 degrees, 60 degrees, and 90 degrees safety selectors No gap with aftermarket pistol grips Upper tension screw allows you to fine-tune fit between upper and lower 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) Accepts Battle Arms Development short-throw safety selectors, but will work with any standard selector Includes nylon-tipped set screw and threaded bolt catch pins Order today!