Aero Precision M4E1 Threaded Barreled AR-15 Upper 5.56 Rifle Atlas S-One – 18″


  • 18” 5.56 NATO
  • 4150 Chrome Moly Vanadium barrel
  • HPT and MPI
  • Black Nitride finish
  • 1:7 twist rate
  • Rifle length gas system
  • M4E1 Threaded forged 7075-T6 upper
  • Hardcoat anodized
  • Laser engraved T-marks
  • Scalloped picatinny top rail
  • Built in anti-rotation tabs
  • M-LOK slots
  • Does not include BCG or charging handle


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SKUAPAR700305M8 Category

Looking for a high-quality barreled upper receiver to start or finish your AR-15 build? Check out the Aero Precision M5 Barreled Upper Receiver! This top-of-the-line upper receiver features a 18” 416R stainless steel barrel chambered in 6.5 Creedmoor, perfect for long range precision shooting and hunting. It also comes with a low profile gas block and mid-length gas system for reliable function. The 15” R-ONE free float handguard provides ample space for accessories and features M-LOK attachment slots for easy mounting of optics, foregrips, lights, and other accessories. The Atlas attachment system is also extremely strong and easy to remove, making this upper receiver perfect for anyone looking to get the most out of their AR-15 build.


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