This complete upper receiver features the same tried-and-true construction and aesthetics as M4E1 Enhanced Upper Receivers, without provisions for a forward assist. The M4E1 Enhanced Upper Receiver is a one-piece design combining the handguard mounting platform with the upper receiver itself. Through superior engineering, we have condensed the parts needed to mount a free-floated handguard to a mere 8 screws. Since the handguard mounting surface and upper are of the same forging, not only is it a stronger system, but we are able to make additional lightening cuts to save weight and allow for more efficient cooling. This complete upper receiver does not include BCG or Charging Handle. Includes: M4E1 Enhanced Upper Receiver, No Forward Assist 9in Gen 2 Enhanced Handguard 16in 5.56 CMV Barrel Low Profile Gas Block and Carbine Length Gas Tube Port Door Assembly A2 Flash Hider Specifications for Aero Precision M4E1 16in 5.56 Enhanced No Forward Assist Complete Upper Receiver with Flash Hider: Manufacturer: Aero Precision Caliber: 5.56x45mm NATO Overall Length: 26 in Barrel Length: 16 in Barrel Profile: Government Gas System Length: Mid Length Barrel Twist Rate: 1-7 Threads per Inch: 1/2x28 Handguard Type: Free-Float Muzzle Device: A2 Flash Hider Gun Model: AR-15 Condition: New Fabric/Material: 416R Stainless Steel Attachment Type: Picatinny Gas Block Journal Size-Diameter: .750 in Handguard Length: 15 in Gun Type: Rifle Gun Make: AR Platform Included Accessories: None Barrel Material: 4150 Chrome Moly Vanadium Bolt Carrier Group Included: No Charging Handle Included: No Weight: 48.5 oz Magazine Included: No Mount Type: M-LOK Country of Origin: USA Features of Aero Precision M4E1 16in 5.56 Enhanced No Forward Assist Complete Upper Receiver with Flash Hider No Forward Assist Custom 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 Handguards M4 Feedramps .250 takedown pin holes Laser engraved T-marks Package Contents: Aero Precision M4E1 16in 5.56 Enhanced No Forward Assist Complete Upper Receiver with Flash Hider This product is compatible with the following gun models: AR-15