-Machined to MIL spec from 7075 T6 forgings
-Top MIL-Std 1913 Rail
-Hardcoat Anodized per MIL-A-8625F, Type III, Class 2
-For Use with M4 Barrel extensions
-Assembled Upper Receivers come with ejection port cover and forward assist installed
-Made in America on American-made machines
-Weight: .8.3oz