Machined from forged 7075 Aluminum, MIL-SPEC Hard Anodizing, Forward assist eliminated for weight saving and reduced snag risk, Lightweight design 6.2 oz stripped (.8 oz lighter than a MIL-SPEC upper receiver) 1.7 oz lighter than a MIL-SPEC upper receiver with hardware installed, Captured dust cover door pin eliminating the need for the E clip, Increased barrel mounting circumference maintaining a solid barrel / receiver interface. Interference fit barrel extension interface for increased accuracy