M4E1 Threaded 18" 5.56 Complete Upper Receiver w/R-ONE Handguard

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
• 18" 5.56 Rifle Length CMV Barrel
• Low Profile Gas Block and Rifle 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

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

18" 5.56 Rifle Length Barrel Features:

• 5.56 Nato 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