Aero Precision M4E1-E Complete Upper, 13.9" 5.56 CMV Mid-Length Barrel, 12.7" Enhanced MLOK HG - FDE Cerakote

Fully Assembled and Warrantied by Aero Precision
SKU: APAR600284M99


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Aero Precision M4E1-E Complete Upper, 13.9″ 5.56 CMV Mid-Length Barrel, 12.7″ Enhanced MLOK HG – FDE Cerakote

The Aero Precision Complete Upper Receiver epitomizes speed, efficiency, and dependability for fashioning a semi-custom AR15 rifle. Crafted with meticulous precision, this 5.56 NATO M4E1 Threaded Complete Upper boasts a 13.9″ Mid-Length barrel and a 12.7″ Gen 2 Enhanced handguard. Meticulously machined, comprehensively assembled, and subject to rigorous test-firing by skilled Aero Precision armorers, it guarantees unparalleled performance.

* NFA Rules apply for this item.
* The muzzle device is NOT pinned nor welded to the barrel.
* Does not include Bolt Carrier Group or Charging Handle.


  • M4E1 Threaded Assembled Upper Receiver – Magpul FDE Cerakote
  • 12.7″ M-LOK Gen 2 Enhanced Handguard – Magpul FDE Cerakote
  • 13.9″ 5.56 NATO Mid-Length Barrel
  • Low-profile Gas Block and Gas Tube
  • Standard A2 Flash Hider

M4E1 Threaded Upper Receiver Features:

  • New enhanced forging gives the upper receiver a “billet look.”
  • M4 Feed ramps
  • .250 takedown pin holes
  • Includes port door and forward assist installed

Gen 2 Enhanced Handguard Features:

  • 1pc free-float design
  • Built-in anti-rotation tabs
  • Scalloped rails
  • Quick disconnect sling socket at the 3, 6, and 9 o’clock positions
  • Compatible with low-profile gas blocks
  • 1.78″ Inside diameter, fits most 1.5″ suppressors
  • Additional milling along flats to aid with gripping and visual appeal
  • New profile for the continuous Picatinny top rail

5.56 NATO Barrel Features:

  • 5.56 NATO 1/7 twist, 4150 CrMoV, QPQ finish
  • .750 gas block journal
  • Mid-Length gas system
  • M4 Feed Ramp Extension
  • HP and MPI tested

Product Information


Aero Precision








12.7" M-LOK


5.56 NATO



Gas System


Twist Rate


Barrel Finish

QPQ Nitride

Muzzle Thread



Enhanced, M4E1


4150 Chrome Moly Vanadium, 6061-T6 Aluminum


Standard AR15 components

Made in USA


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

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