Aero Precision AR .308 Upper Parts Kit Black. 308) Upper Receiver. Specifications for Aero Precision AR .308 Upper Parts Kit: Manufacturer: Aero Precision Color: Black Finish: Parkerized Caliber: .308 Winchester Gun Model: M5 Condition: New Country of Origin: USA Package Contents: Aero Precision AR .308 Upper Parts Kit Forward Assist Assembly Forward Assist Spring Forward Assist Roll Pin Ejection Port Cover Door Ejection Port Cover Rod Ejection Port Cover Spring What firearm models does the manufacturer say Aero Precision AR .308 Upper Parts Kit is compatible with? The manufacturer suggests that Aero Precision AR .308 Upper Parts Kit is compatible with M5Aero Precision APRH101237: AR .308 Upper Parts Kit Black