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Aero Precision

Aero Precision Aero Precision M4E1 Threaded Barreled Upper Receiver .300 BLK Pistol Length - ATLAS S-ONE - 8"

Product Code : APAR700301M1


Mfg Item #: APAR700301M1

Note: This barreled upper receiver assembly has a barrel length under 16” and is therefore subject to all NFA rules and regulations. Know your local laws before purchasing.

This Aero Precision M4E1 Threaded upper receiver group comes completely assembled with 8” .300 Blackout barrel and a pistol length gas system to ensure reliable function. Forged from 7075-T6 aluminum, this upper receiver features a billet design at a much lower cost and looks great when paired with the M4E1 lower receiver. The ATLAS S-ONE free float handguard is made from the same material with the same hardcoat anodized finish and features a lightened profile with M-LOK slots for accessories. This .300 Blackout AR-15 barreled upper receiver assembly does not include a BCG or charging handle but does include the forward assist and dust cover. Build a high quality .300 BLK AR pistol today with the M4E1 upper receiver assembly.


  • M4E1 threaded upper receiver
  • Forged 7075-T6 aluminum
  • Assembled forward assist and dust cover
  • 7” ATLAS S-ONE M-LOK handguard
  • Hardcoat anodized
  • 8” .300 Blackout barrel
  • Machined from Chrome Moly Vanadium
  • Pistol length gas system
  • 1:7 twist rate
  • Threaded 5/8x24
  • A2 flash hider
  • Salt Bath Nitride finished
  • Does not include BCG or charging handle

The 8” barrel is machined from Chrome Moly Vanadium steel with a salt bath Nitride finish and a 1:7 twist rate for stabilizing heavier rounds. It is threaded 5/8x24 with an A2 style flash hider. High pressure tested and magnetic particle inspected ensure this barrel is accurate and reliable. This Aero Precision AR-15 barreled upper is a great choice for finishing an AR build.

Barrel ContourMedium
Barrel Length8.0
Barrel MaterialChrome Moly Vanadium
BrandAero Precision
Caliber Gauge300 Blackout
Gas System LengthPistol
Gas System TypeDirect Impingement
Handguard7 in M-LOK Rail
Muzzle DeviceA2 Flash Hider
Twist Rate1:7

Determined at checkout.