Aero Precision M4E1 Threaded Assembled Receiver Set

Aero Precision M4E1 Threaded Assembled Receiver Set 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