Aero Precision M4e1 Threaded Assembled Receiver Sets

M4E1 Lower Receiver Features: 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). 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 – Allow Mfg: Aero Precision