This complete upper receiver features the same tried-and-true construction and aesthetics as our 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. Our 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.

Includes:

• M4E1 Threaded Upper Receiver, No Forward Assist
• 9.2" ATLAS R-ONE Handguard
• 10.5" 5.56 CMV Barrel
• Low Profile Gas Block and Carbine Length Gas Tube
• Port Door Assembly
• A2 Flash Hider
• This complete upper receiver does not include BCG or Charging Handle. 

M4E1 Threaded, No Forward Assist Upper Receiver Features:

• 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

ATLAS R-ONE Handguard Features:

• Full top picatinny rail for optional attachments
• Quick disconnect sling socket at the 3, 6 and 9 o'clock positions
• 1.3" Inside diameter
• 1.5" Outside diameter
• Compatible with mil-spec AR15 upper receivers and barrels
• MLOK attachment points

10.5" 5.56 Barrel Features:

• 5.56 NATO 10.5" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
• .750 gas block journal
• Carbine length gas system, .0785 gas port
• M4 Feed Ramp Extension
• HP and MPI tested
• Standard A2 flash hider