MPN: APAR700304M5 / APAR700704M5 / APAR700314M5 / APAR700714M5


  • Caliber: 5.56 NATO
  • Finish: Type III Class 2 Hardcoat Anodized or Cerakote Flat Dark Earth
  • Upper Receiver: Aero Precision M4E1 Threaded Upper - 7075-T6 Aluminum
  • Handguard: 12.7-Inch ATLAS S-ONE or R-ONE M-LOK Handguard
  • M4 Feed Ramps: Yes
  • Muzzle Device: A2 Flash Hider
  • Barrel: 14.5" 1:7 QPQ Coated 4150 Chrome Moly Vanadium Barrel
  • Muzzle Thread Pattern: 1/2"-28 TPI
  • Gas Block: Aero .750" Low-Profile Gas Block
  • Gas Tube: Mid-Length Gas Tube
  • Bolt Carrier Group: Not Included
  • Charging Handle: Not Included
  • MPI and HP Tested

*This upper assembly does not come with Bolt Carrier Group and Charging Handle

*ATLAS S-ONE Handguard: Front and rear picatinny rail section. Eliminated center of top rail for weight reduction.

*ATLAS R-ONE Handguard: Full top picatinny rail

*This upper receiver assembly has a barrel that is shorter than 16". This upper is only for use on AR pistol lower receivers and NFA registered Short-Barreled Rifle (SBR) lower receivers. All NFA laws apply!


  • Weight: ~2.98 lbs.
  • Length: ~22.95"


  • AR-15 lower receiver


  • 1x  Aero Precision 14.5" 5.56 M4E1 Mid-Length Complete Upper Assembly


Aero Precision makes some of the best AR parts and Accessories in the US, and their M4E1 Complete Upper Assemblies are an excellent option for anyone looking to build an AR15. They are available in multiple calibers and configurations. However, this one is chambered in 5.56 and comes with a 14.5" barrel.

The barrel is made from 4150 Chrome Moly Vanadium steel, which is QPQ coated for better corrosion resistance. The barrel is also threaded and comes with an A2-style flash hider from the factory. The gas system on this upper has a low profile and uses a mid-length gas tube.

Like most M4E1 uppers from Aero Precision, this one also comes with your choice of handguard. You can choose between the Aero precision Atlas S-One or R-One handguards. Both of these rails are made from Aluminum and have M-LOK compatibility. The R-One has a complete top Picatinny rail, whereas the S-One is designed to be lighter and only has a small section of Picatinny rail on the front and back of the handguard.

The Aero Precision M4E1 receiver is made from 7075-T6 Aluminum and features a forward assist and port door. It also has M4 feed ramps for better performance.


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  • This Item: Aero Precision 14.5" 5.56 M4E1 Mid-Length Complete Upper Assembly
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