Aero Precision

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 15" ATLAS R-ONE Handguard 16" 5.56 CMV Barrel Low Profile Gas Block and Mid-Length Gas Tube Port Door Assembly A2 Flash Hider This complete upper receiver does not include BCG or Charging Handle. These products may be selected as add-ons under the FINISH YOUR BUILD tab. 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 16" 5.56 Barrel Features: 5.56 NATO 16" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled .750 gas block journal Mid length gas system, .0785 gas port M4 Feed Ramp Extension HP and MPI tested Standard A2 flash hider