The M4E1 Threaded Upper Receiver features a new angular machined design that helps it stand apart from standard mil-spec upper receivers. This upper receiver features the same enhanced body profile as their M4E1 Enhanced Upper Receiver but is threaded to accept a standard AR15 barrel nut. It is forged from 7075-T6 Aluminum, precision machined to work with all mil-spec AR15 parts and includes the port door and forward assist pre-installed.The M4E1 Threaded Upper Receiver is designed to pair perfectly with their M4E1 Lower Receiver, giving you a billet looking receiver set at a fraction of the billet price. FeaturesNew enhanced forging that gives the upper receiver a "billet look"New picatinny profile that blends seamlessly with their Enhanced and ATLAS Series HandguardsM4 Feedramps.250 takedown pin holesIncludes threaded forward assist roll pinIncludes port door and forward assist Includes:M4E1 Threaded Upper ReceiverPort Door and Forward Assist installed