Aero Precision M4E1 Threaded AR-15 Barreled Upper Receiver 5.56 Carbine – ATLAS S-ONE – 11.5″


  • M4E1 threaded upper receiver
  • Forged 7075-T6 aluminum
  • Assembled forward assist and dust cover
  • 9” ATLAS S-ONE M-LOK handguard
  • Hardcoat anodized
  • 11.5” 5.56 NATO barrel
  • Machined from Chrome Moly Vanadium
  • Carbine length gas system
  • 1:7 twist rate
  • Threaded 1/2×28
  • A2 flash hider
  • Salt Bath Nitride finished
  • Does not include BCG or charging handle


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SKUAPAR700302M29 Category

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.

Looking to start or complete your AR-15 build with a high-quality upper receiver group? Check out the Aero Precision M4E1 Threaded AR-15 Barreled Upper Receiver 5.56 Carbine – ATLAS. This complete upper receiver group comes with an 11.5” 5.56 barrel and the ATLAS S-ONE M-LOK handguard already installed, so you can start shooting right away. The forged 7075-T6 aluminum upper receiver has a billet machined look that matches perfectly with the included lower and handguard.

Aero Precision’s M4E1 Threaded AR-15 Barreled Upper Receiver is a perfect choice for anyone looking to build a high-quality AR-15. The 11.5″ barrel is machined from Chrome Moly Vanadium steel with a salt bath Nitride finish, and features a 1:7 twist rate for stability with heavier rounds. It is threaded 1/2×28 with an A2 style flash hider that has not been pinned and welded, meaning it can be attached to a pistol lower receiver. High pressure testing and magnetic particle inspection ensure this barrel is accurate and reliable.



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