Add power, precision, and expanded customization options to your rifle with an Aero Precision M5E1 .308 Barrel Complete Upper Receiver. While there’s several options to choose from, all of these AR15 Upper Receivers brought to you by Aero Precision feature a precision machined 7075 T6 aluminum upper for added strength that won’t weigh you down in the field. For ease of use, the Aero Precision M5E1 .308 Barrel Complete KeyMod Upper Receiver comes with the forward assist and port door installed, and the handguard mounting platform is forged right into the receiver.