This complete upper receiver features the same tried-and-true construction and aesthetics as M4E1 Threaded Upper Receivers, without provisions for a forward assist. The included ATLAS R-ONE Handguard is designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. proprietary ATLAS attachment system is a durable and dependable mounting platform, maintaining a slim profile while still providing the strength and stability customers have grown to love from Aero Precision handguards. This complete upper receiver does not include BCG or Charging HandleIncludes:M4E1 Threaded Upper Receiver, No Forward Assist9.2in ATLAS R-ONE Handguard10.5in 5.56 CMV BarrelLow Profile Gas Block and Carbine Length Gas TubePort Door AssemblyA2 Flash HiderFeatures:No Forward AssistCustom enhanced forging that gives the upper receiver a "billet look" while maintaining the structural integrity of a forged part.Picatinny profile that blends seamlessly with our Enhanced and ATLAS Series HandguardsM4 Feedramps.250 takedown pin holesSpecifications:Manufacturer: Aero PrecisionCartridge: 5.56x45mm NATOBarrel Length: 10.5 inGas System Length: Carbine LengthBarrel Twist Rate: 1-7Handguard Type: Free-FloatMuzzle Device: A2 Flash HiderGun Model: AR-15Condition: NewFabric/Material: 416R Stainless SteelAttachment/Mount Type: M-LOK, PicatinnyGas Block Journal Size-Diameter: .750 inHandguard Length: 9.2 inGun Rail: Full Top RailGun Type: RifleGun Make: AR PlatformBarrel Material: 4150 Chrome Moly VanadiumBolt Carrier Group Included: NoCharging Handle Included: No