Aero Precision 300 Blackout M4E1 ATLAS R-ONE Complete Upper

SKU: APPG700213
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Fully Assembled and Warrantied by Aero Precision
Ballistic Advantage Authorized DealerAero Precision Authorized Dealer

Aero Precision 300 Blackout M4E1 ATLAS R-ONE Complete Upper

Available in black or FDE with your choice of 3 barrel lengths.

Aero Precision 300 Blackout M4E1 ATLAS R-ONE Complete Upper is the most efficient way to assemble your 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.
**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 gives the upper receiver a “billet look.”
  • M4 Feed ramps
  • .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

300 BLK Barrel Features:

  • Select between an 8″, 10″, or 16″ barrel.
  • .300 Blackout 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
  • .750 gas block journal
  • Gas Port: .0935
  • Pistol-length gas system.
  • M4 Feed Ramp Extension
  • M4 Barrel Extension
  • HP and MPI tested
  • Standard A2 flash hider

Choose between 3 Configurations:

APAR700701M1 / APAR700711M1 – 8″ Barrel w/ 7″ ATLAS R-ONE MLOK
APAR700702M4 / APAR700712M4 – 10″ Barrel w/ 9″ ATLAS R-ONE MLOK
APAR700705M14 / APAR700715M14 – 16″ Barrel 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
  • 8″, 10″, or 16″ 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 with this complete upper receiver is NOT pinned nor welded to this barrel.

Product Information




300 Blackout


4150 Chrome Moly Vanadium, 6061-T6 Aluminum, 7075-T6 Aluminum

Coating Type

Black Anodize, Magpul FDE Cerakote

Attachment Type


Gas System


Barrel Length

8", 10", 16"

Gas Block Diameter


Muzzle Thread



Standard AR15 components

Made in USA



Aero Precision

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