The CMMG Banshee Mk3 8.6 BLK upper group (CMMG part no. 33B430C-AB) pairs the 8.6 Blackout cartridge with a short 12.5-inch barrel and a fast 1:3 twist rate. CMMG builds it on the Mk3 platform, which is based on the popular DPMS Gen 1 high-pattern LR308 design. It is aimed at shooters who want to swap uppers on an existing Mk3 build or start a new one around 8.6 BLK. The Cerakote finish here is Armor Black, and the upper comes as a complete group with its bolt carrier group, ZEROED polymer dust cover and ZEROED ambidextrous charging handle.

Key Specifications

• Caliber is 8.6 BLK, a cartridge that CMMG pairs with a quick twist so it performs well from a short barrel.
• Barrel length is 12.5 inches, a compact length that keeps a Mk3 build short and handy.
• Barrel twist is 1:3, the fast rate that this cartridge relies on to stabilize its bullets.
• The barrel is made from 4140CM steel with an SBN treatment, a salt bath nitride finish for wear and corrosion resistance.
• The muzzle device is a CMMG ZEROED SVB brake, which controls muzzle movement and gives you a ready-fitted device.
• Muzzle threading is 5/8×24, the common pitch for muzzle devices and accessories.
• The gas system is direct impingement with a pistol-length gas port, set up for a short barrel.
• The gas block is an adjustable .750-inch unit, which lets you tune the system to your ammunition.
• The upper receiver is billet 7075-T6 aluminum, a strong, light material that CMMG machines to size.
• The handguard is the EML11 M-LOK model, so lights, grips and other accessories mount directly to it.

Frequently Asked Questions

Does this upper include a bolt carrier group? Yes. CMMG states that its Upper Groups come complete with a bolt carrier group, and this one also ships with a ZEROED polymer dust cover and a ZEROED ambidextrous charging handle.

What platform is the Mk3 upper built on? The CMMG Mk3 platform is based on the popular DPMS Gen 1 high-pattern LR308 design, so it is meant for swapping onto or building out a Mk3 rifle or pistol.

What finish does this upper carry? This listing is the Armor Black Cerakote finish. CMMG offers the same upper group in other Cerakote colors.

Buy the CMMG Banshee Mk3 8.6 BLK Upper Group, 12.5-Inch, Armor Black

A short 8.6 BLK barrel only makes sense with the right twist, and this upper brings the 1:3 rate, an adjustable gas block and a ZEROED brake together in one complete group. It is a straightforward way to give a Mk3 lower an 8.6 Blackout personality. Order it with our other AR-10 uppers from our Lubbock, Texas gun shop for fast, insured shipping.