This assembled upper includes Aero Precision’s new ATLAS S-ONE Handguard! The S-ONE line of handguards are designed with size and weight in mind, providing the perfect addition to your lightweight build. Aero Precision’s 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.

FEATURES:

• M4E1 Threaded Assembled Upper Receiver
• Choice of 12” or 15” M-LOK ATLAS S-ONE Handguard
• 16" 5.56 Mid CMV Barrel, 18” Rifle Barrel
• Low Profile Gas Block and Mid-Length/Rifle Length Gas Tube Depending on Configuration
• Product comes assembled
• This assembled upper does not include BCG or Charging Handle
• New enhanced forging that gives the upper receiver a "billet look"
• New picatinny profile that blends seamlessly with Aero's Enhanced Series Handguards
• M4 Feedramps
• .250 takedown pin holes
• Laser engraved T-marks
• Includes port door and forward assist installed

ATLAS S-ONE Handguard Features:

• Front and rear picatinny rail
• Eliminated center of top rail for weight reduction
• Indexing grooves in 12:00 position for positive grip control
• 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

• 5.56 Nato 11.5" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
• Government Profile
• .750 gas block journal
• Carbine length gas system, .0785 gas port
• M4 Feed Ramp Extension
• HP and MPI tested
• Standard A2 flash hider

16" 5.56 Mid Barrel Features:

• 5.56 NATO 16" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
• Mid-length gas system, .0785 gas port
• M4 Feed Ramp Extension
• HP and MPI tested
• Standard A2 flash hider

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