Aero Precision

M4E1 Lower Receiver Improvements: Threaded Bolt Catch Roll Pin - Allows for simple installation of the bolt catch and virtually eliminates the chance to damage the finish during installation (pin included). 1/16" Hex Key required for assembly. Integrated Trigger Guard - Eliminates the possibility of breaking the trigger guard tabs by integrating the trigger guard into the lower, creating a stronger more rigid platform to build upon. Upper Tension Screw - Allows users to fine tune the fit of the upper and lower receiver using a nylon tipped tensioning set screw inserted in the grip tang of the lower receiver. This provides a tight fit with any standard AR15 upper receiver. Threaded Takedown Pin Detent Recess - Allows user to easily install the Takedown Pin detent and spring with the use of a 4-40 set screw (no more launching detents across the room). Increased Magwell Flare - Increased the flare of the magwell to aid in quick and efficient magazine changes. Marked and milled to accept short-throw safety selectors, but will work with standard selectors as well. Includes: Stripped M4E1 Lower Receiver Nylon tipped tensioning set screw Threaded Bolt Catch Pin   SPECS Specs Shipping to FFL Dealer Required Yes Made In America? Yes Platform AR15 Material Machined from 7075-T6 forged aluminum Finish Magpul FDE Cerakote Markings "Cal Multi", "M4-" Serial Number Designation Compatibility Works with standard AR15 components and magazines Weight(s) 8.61 oz Other Rear takedown pin detent hole is threaded for a 4-40 set screw. Threaded Bolt Catch Roll Pin (Included).