• Caliber: 5.56 NATO
  • Finish: Armor Black Cerakote
  • Upper Receiver: CMMG Mk4 Upper Receiver - 6061-T6 Aluminum
  • Handguard: 15-Inch CMMG EML15 Handguard
  • M4 Feed Ramps: Yes
  • Muzzle Device: CMMG A2 Flash Hider
  • Barrel: 16.1" 1:7 Salt Bath Nitrided 4140 Chrome Moly Steel
  • Muzzle Thread Pattern: 1/2"-28
  • Gas Block: CMMG.750" Low-Profile Gas Block
  • Gas Tube: Mid-Length Gas Tube
  • Bolt Carrier Group: Not Included
  • Charging Handle: Not Included
  • HP and MPI Tested

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


  • Weight: ~3.37 lbs.
  • Length: ~24.56"


  • AR-15 lower receiver


  • 1x CMMG Resolute 5.56 NATO 16.1" MK4 Upper Assembly


If you want unmatched reliability and performance from your next AR-15 build, check out the CMMG Resolute 5.56 NATO 16.1" MK4 Upper Assembly.

This upper assembly features the MK4 upper receiver, made from durable 6061-T6 aluminum. It offers a reliable, lightweight, and robust platform for your AR-15. To add to its appeal, this upper receiver is coated with a sleek Armor Black Cerakote finish, giving it a cool look and providing protection against corrosion for the receiver. Moreover, with its excellent M4 feed ramps, this receiver ensures reliable cycling of ammunition and flawless operation in any situation.

Durable and Accurate

Moving on, this upper assembly comes with a 16.1-inch rifle-length barrel. Forged from highly durable 4140 Chrome Moly Steel, this barrel is also made to be extremely durable and accurate. The barrel is threaded with a standard 1/2"-28 thread pitch and equipped with a CMMG A2 Flash Hider.

To ensure the proper cycling of your firearm, this upper assembly is equipped with the CMMG .750 '' Low-Profile Gas Block uses a mid-length gas tube for reliable weapon operation without over-gassing.

The gas block and barrel are covered by the 15-Inch CMMG EML15 Handguard. This aluminum handguard comes with M-LOK sloths on both sides and the bottom, along with two small sections of Picatinny rail on the top for mounting sights.

Craftsmanship and Quality

The CMMG Resolute 5.56 NATO 16.1" MK4 Upper Assembly combines high-end craftsmanship with superior materials and uses the highest industry standards for quality assurance. The parts of this upper assembly are HP and MPI tested, so you can trust them to stand the test of time and offer reliable performance every time.

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  • This Item: CMMG Resolute 5.56 NATO 16.1" MK4 Upper Assembly
    MSRP: $559.95
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