Aero Precision M4E1 Threaded Complete Upper 5.56 18 Barrel

This assembled upper includes Aero Precisions new ATLAS R-ONE Handguard! The R-ONE handguards are designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. Their 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 Assembled Upper Receiver - Anodized Black 15" ATLAS R-ONE M-LOK Handguard with 16"CMV Barrel OR 15" ATLAS R-ONE M-LOK Handguard 18" Rifle Length CMV Barrel Low Profile Gas Block and Mid Pencil, Mid-Length, or Rifle Length Gas Tube depending on configuration Product comes assembled This assembled upper does not include BCG or Charging Handle. The muzzle brake that comes with this assembled upper receiver is NOT pinned nor welded to this barrel. Per the National Firearms Act, the muzzle brake MUST be pinned and welded to achieve the necessary 16"" as defined by the ATF for a rifle build. M4E1 Threaded Upper Receiver Features: New enhanced forging that gives the upper receiver a "billet look" New picatinny profile that blends seamlessly with our Enhanced Series Handguards M4 Feedramps .250 takedown pin holes Laser engraved T-marks Includes port door and forward assist installed 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 Compatible with low profile gas blocks 1.3 Inside diameter 1.5 Outside diameter Compatible with mil-spec AR15 upper receivers and barrels 18" Rifle Length Barrel Features: 18" Rifle Length Barrel 4150 CrMoV w/ QPQ finish 1/7 twist .750 gas block journal Rifle length gas system M4 Feed Ramp Extension HP and MPI tested Standard A2 flash hider