Aero Precision M4E1 Enhanced AR-15 Upper Receiver with Forward Assist

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AT3™ AR-15 Bolt Carrier Group -  5.56 NATO/.300 Blackout - Black Nitride

AT3™ AR-15 Bolt Carrier Group – 5.56 NATO/.300 Blackout – Black Nitride


AT3™ AR-15 Bolt Carrier Group -  5.56 NATO/.300 Blackout - Black Nitride

AT3™ AR-15 Bolt Carrier Group (BCG) – 5.56 NATO/.300 Blackout – Black Nitride

Enhanced M4E1 Upper with Internal Barrel Nut

The Aero M4E1 Enhanced Upper has a unique design and core function that separates it from standard AR-15 uppers. Instead of the typical threading for a barrel nut, the enhanced upper has a built-in assembly to support Aero Precision’s Enhanced Handguards. The internal steel barrel nut supports the barrel exclusively – effectively eliminating deflection when mounting laser modules to the handguard.

This upper receiver features the same enhanced body profile as the threaded M4E1 Upper Receiver, so it matches with M4E1 lowers. It is forged from 7075-T6 Aluminum, precision machined to work with mil-spec AR15 parts, and includes the port door and forward assist pre-installed.

Note: This upper receiver will not work with standard handguards. Use Aero Precision Enhanced or Quantum series handguards only.


  • M4 Feedramps
  • .250 takedown pin holes
  • Comes assembled, with dust cover and forward assist installed

M4E1 Specific Details:

  • Handguard mounting platform is forged into the receiver
  • Compatible with Aero Precision Enhanced and Quantum Series handguards but also fits most BAR-system handguards
  • Barrel nut and wrench are included
  • These uppers are not piston-kit compatible
  • Will support barrels with a diameter up to 1″


  • AR15 M4E1 Enhanced Upper Receiver
  • Port Door and Forward Assist installed
  • Barrel nut
  • Barrel nut wrench


  • Platform: AR15
  • Material: Machined from 7075-T6 forged aluminum
  • Finish: Anodized Black or Magpul Flat Dark Earth Cerakote
  • Compatibility: Works with standard AR15/M16 components
  • Weight(s): 12.4 oz
  • Barrel Nut Torque – 55 ft-lbs
  • Made In America: Yes

Have Questions About this Product?

The AT3 Tactical store has a 90 day no-hassle return policy for products in good condition. You can view the full details of our return policy here.

If you encounter an issue or defect with a product after 90 days of your purchase, you can refer to the manufacturer for a warranty claim. Their policies are below.

Aero Precision Warranty

If for any reason you have a warranty issue with one of our products, please contact us at 253-272-8188.

Please describe your situation, include your name and order number or transaction id. One of our technical specialists will then review your claim and contact you within 3-5 business days.

If you have images to send, please email them to

Damaged Items

In regards to claims dealing with damaged or blemished products, we ask that you create a Help Desk Ticket on your My Account page. If you don’t have an account with us, please go to the Contact Us page and fill out the form for review within 72 hours upon receiving the shipment.

If you have images to send, please email them to

Failed Background Check

There will be a 30% restocking fee on all lower receivers returned because of failed background checks.

Disclaimer: Manufacturer’s warranty is subject to change without prior notice.

Customer Reviews

Based on 1 review
Great product!

It’s hard to beat the quality and function of the Aero Precision brand. The uppers and lowers are a go to for my builds. The enhanced version simplifies the installation of the AP hand guards if a builder decides to go that route.

Thanks for sharing your feedback! We're glad you're satisfied with your purchase.