The CMMG Banshee Upper Group (brand part no. 99B9A0F-AB) pairs an 8-inch, 4140CM steel barrel with CMMG’s fixed-ejector radial delayed blowback system for carbine-like performance in a compact 9mm Luger AR upper. It is built to run on CMMG’s Mk4, Mk9, Mk17, and MkGs lowers, or on a mil-spec AR-15 lower using CMMG’s 9mm conversion magazines, giving shooters several lower and magazine pairing options. The billet 6061-T6 aluminum upper receiver comes complete with a bolt carrier group, a CMMG EML7 M-LOK free-float handguard, a ZEROED ambidextrous charging handle, and a ZEROED linear compensator threaded 1/2×28. Finished in Cerakote Armor Black and weighing roughly 3.0 lb, it is built for shooters who want a fast-handling, easy-to-suppress 9mm AR.

Key Specifications

• Caliber and barrel: 9mm Luger, with an 8-inch, 4140CM steel barrel finished with a salt-bath nitride process.
• Twist rate: 1:10, matched to common 9mm Luger bullet weights.
• Operating system: fixed-ejector radial delayed blowback, CMMG’s dedicated 9mm AR operating system.
• Muzzle device: CMMG ZEROED linear compensator, threaded 1/2×28 for common muzzle devices.
• Upper receiver: billet 6061-T6 aluminum, for a precise, durable upper.
• Handguard: CMMG EML7 M-LOK, a free-float rail for mounting accessories.
• Charging handle and weight: CMMG ZEROED ambidextrous charging handle, on a complete upper group weighing roughly 3.0 lb.

Frequently Asked Questions

What lowers does this 9mm upper work with? It is designed to run on CMMG MkGs or Mk17 lowers, or a mil-spec AR-15 lower paired with CMMG’s 9mm conversion magazine.

Does it come with a bolt carrier group? Yes, it ships complete with a bolt carrier group and CMMG’s ZEROED accessories.

What is radial delayed blowback? It is CMMG’s fixed-ejector operating system built specifically for reliable 9mm cycling in an AR platform, rather than a direct-blowback or gas-impingement design.

Buy the CMMG Banshee 9mm Upper Group

Build the ultimate compact 9mm AR without starting from scratch — order the Banshee Upper Group from Schaefer Defense and browse our full AR-15 uppers lineup for more caliber and barrel-length options. Ships fast from our Lubbock, Texas gun shop.