Aero Precision 300 Blackout M4E1 ATLAS S-ONE Complete Upper

SKU: APPG700212
Fully Assembled and Warrantied by Aero Precision.
Ballistic Advantage Authorized DealerAero Precision Authorized Dealer

Aero Precision 300 Blackout M4E1 ATLAS S-ONE Complete Upper

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

Aero Precision 300 Blackout M4E1 ATLAS S-ONE Complete Upper is the most efficient way to assemble your custom firearm, fully assembled and warrantied by Aero Precision.  The S-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 that 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 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

300 BLK Barrel Features:

  • Select between a 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:

APAR700301M1 / APAR700311M1 – 8″ Barrel w/ 7″ ATLAS S-ONE MLOK
APAR700302M4 / APAR700312M4 – 10″ Barrel w/ 9″ ATLAS S-ONE MLOK
APAR700305M14 / APAR700315M14 – 16″ Barrel w/ 15″ ATLAS S-ONE MLOK

Also available with the ATLAS R-ONE Handguards


  • M4E1 Threaded Assembled Upper Receiver
  • M-LOK ATLAS S-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


Black, FDE

Barrel Length

8", 10", 16"

Gas System


Gas Block Diameter


Muzzle Thread



300 Blackout

Attachment Type


Arm or Ally

Arm or Ally is a stocking dealer for all Aero Precision, Faxon Firearms, Ballistic Advantage, HOLOSUN, Toolcraft, Elftmann Tactical, Timney, TriggerTech, HIPERFIRE and named the #1 Overall E-Commerce Dealer for Aero Precision Products in 2020!

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