Aero Precision 5.56 NATO M4E1 ATLAS R-ONE Complete Upper



Fully Assembled and Warrantied by Aero Precision
SKU: M4E1-CU-ATLAS-R Categories: , , Tags: ,

Aero Precision 5.56 NATO M4E1 ATLAS R-ONE Complete Upper

Available in 10.5" Carbine or 16" Mid-Length

Aero Precision 5.56 NATO M4E1 ATLAS R-ONE Complete Upper is the most efficient way to assemble your own custom firearm; fully assembled and warrantied by Aero Precision. The R-ONE 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.

*NFA Rules apply for the 10.5" barreled model.
**The muzzle devices are NOT pinned nor welded to the barrel.
***Does not include Bolt Carrier Group or Charging Handle.

M4E1 Threaded Upper Receiver Features:

  • New enhanced forging that gives the upper receiver a "billet look"
  • 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

5.56 Barrel Features:

  • Select between a 10.5" Carbine or 16" Mid-Length barrel
  • 5.56 NATO 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
  • .750 gas block journal
  • Carbine length gas system (10.5") | Mid-Length Gas (16")
  • .0785 gas port
  • M4 Feed Ramp Extension
  • HP and MPI tested
  • Standard A2 flash hider

Choose between 2 Configurations:

APAR700702M2 - 10.5" Carbine w/ 9" ATLAS R-ONE MLOK
APAR700705M7 - 16" Mid w/ 15" ATLAS R-ONE MLOK

Also available with the ATLAS S-ONE Handguards


  • M4E1 Threaded Assembled Upper Receiver
  • M-LOK ATLAS R-ONE Handguard
  • 10.5" or 16" 5.56 CMV Barrel
  • Low Profile Gas Block and Gas Tube
  • Product comes assembled
  • This complete upper does not include BCG or Charging Handle.
  • The muzzle brake that comes with this complete upper receiver is NOT pinned nor welded to this barrel.


Product Information

Manufacturer: Aero Precision
Brand: Aero Precision
SKU: APAR700702M2 | APAR700705M7
Assembled: Yes
Finish: Anodize
Color: Black
Caliber: 5.56 NATO
Platform: AR15
Complete Upper Series: ATLAS
Handguard Dims: OD: 1.5" | ID: 1.3"
Handguard Type: M-LOK
Gas Block Diameter: .750
Muzzle Device: A2 Flash Hider
Muzzle Threads: 1/2x28 TPI
Barrel Length: 10.5" | 16"
Barrel Finish: QPQ Melonite
MSRP: $434.99 to $484.99

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Weight N/A
Dimensions N/A
Barrel Length

10.5", 16"

Gas System

Carbine, Mid-Length

Gas Block Diameter


Muzzle Thread

1/2 x 28


5.56 NATO

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