Aero Precision M4E1-T AR-15 Receiver Set Black

The Aero Precision M4E1 Threaded Receiver Assembly Set includes the M4E1 Lower Receiver and the M4E1 Threaded Assembled Upper Receiver.M4E1 Lower Receiver FeaturesThreaded 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 r