• Caliber: .300 Blackout
  • Finish: Armor Black Cerakote
  • Upper Receiver: CMMG Mk4 Upper Receiver - 6061-T6 Aluminum
  • Handguard: 11-Inch CMMG EML11 Handguard
  • M4 Feed Ramps: Yes
  • Muzzle Device: CMMG .308 ZEROED Linear Compensator
  • Barrel: 12.5" 1:7 Salt Bath Nitrided 4140 Chrome Moly Steel
  • Muzzle Thread Pattern: 5/8"-24
  • Gas Block: CMMG.750" Low-Profile Gas Block
  • Gas Tube: Pistol-Length Gas Tube
  • Bolt Carrier Group: Mil-Spec M16 Bolt Carrier Group
  • Charging Handle: CMMG ZEROED AR15 Ambi Charging Handle
  • HP and MPI Tested

*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: ~3.62 lbs.
  • Length: ~20.44"


  • AR-15 lower receiver


  • 1x CMMG Banshee 300 Blackout 12.5" MK4 Complete Upper
  • 1x Mil-Spec M16 Bolt Carrier Group
  • 1x CMMG ZEROED AR15 Ambi Charging Handle


The CMMG Banshee is a very popular rifle, and if you are looking to build one chamber in .300 Blackout, you should check out the CMMG Banshee 300 Blackout Complete Upper.

The .300 Blackout is a very capable short-range caliber. It has a lot of stopping power and can be used in any AR-15 magazine, with a standard AR lower and bolt carrier group as well. This CMMG Banshee .300 Blackout Upper comes with a 12.5" Salt Bath Nitrided 4140 Chrome Moly Steel barrel. This incredible barrel is stronger than normal stainless steel barrels and is more corrosion-resistant as well. It has a 5/8"-24 thread profile and comes equipped with a CMMG .308 ZEROED Linear Compensator, which really helps in mitigating the felt recoil of the .300 Blackout.

This upper features a low-profile gas block with a pistol-length gas tube. This works perfectly with the .300 blackout caliber, which can reach its maximum burning potential in a 9-inch barrel. This upper comes with an 11-Inch CMMG EML11 Handguard. This lightweight handguard has M-Lok sloths on both sides and the bottom, whereas the top has two small sections of Picatinny rail on the front and rear of the handguard. This free-floating handguard is mounted to the receiver using anti-rotation pins.

The CMMG Banshee 300 Blackout MK4 receiver is made from 6061-T6 Aluminum. It has a .300 Blackout chamber with M4 feed ramps and uses a Mil-Spec M16 Bolt Carrier Group. BCG and the barrel on this upper Assembly are both MPI and HP Tested to ensure the strength and quality of the steel. This upper also includes the ZEROED Ambidextrous Charging Handle from CMMG.

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