Discontinued: Aero Precision M4E1 Enhanced Slick Side AR-15 Upper Receiver

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Aero Precision Gen 2 Enhanced M-LOK AR-15 Handguard - Flat Dark Earth - 15 inch


This product has been discontinued by Aero Precision, but we have limited quantities available!

Slick Side M4E1 Upper with Internal Barrel Nut

This Aero M4E1 Enhanced Upper eliminates the forward assist, and features a new method for supporting Aero’s Enhanced handguards. Rather than standard barrel nut threads, the enhanced upper has an internal barrel nut, and a separate handguard mounting platform. This unique method of separating barrel and handguard significantly reduces 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. Aero forges these uppers from 7075-T6 Aluminum, precision machined to work withmil-spec AR15 parts, and includes the ejection port door pre-installed. The internal barrel nut and required wrench are also included.

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 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 Slick Side Upper Receiver
  • Ejection Port Door 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: 11.28 oz
  • Barrel Nut Torque – 55 ft-lbs
  • Made In America: Yes

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