This complete upper includes our 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. 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 Assembled Upper Receiver
• ATLAS R-ONE Handguard of choice
• 14.5″ 5.56 Mid-Length CMV Barrel
• Low Profile Gas Block and Mid Length Gas Tube
• Product comes assembled
• This complete upper does not include BCG or Charging Handle. These products may be selected as add-ons under the FINISH YOUR BUILD tab
• The muzzle brake that comes with this complete 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
• Learn More about our NEW ATLAS Handguards

14.5″ 5.56 Mid-Length Barrel Features:

• Chamber: 5.56
• Length: 14.5″
• Twist: 1 in 7
• Threading: 1/2″x28
• Material: Chrome Moly Vanadium
• Finish: QPQ corrosion resistant finish both inside and out
• Gas Block: .750
• Gas Port: .0785
• Gas System Length: Mid
• Weight: 26oz
• M4 Barrel Extension
• HP and MPI Tested