CMMG Banshee MK4 Fixed Ejector Handgun 9mm Luger 30rd Magazine 8" Barrel RipBrace Armor Black

The CMMG Banshee MK4 is a purpose-built 9mm AR pistol that brings familiar AR-15 ergonomics and controls to a compact, maneuverable platform. Whether you're looking for a personal defense firearm, a range toy, or a truck gun, the Banshee MK4 delivers AR reliability in a form factor that handles tight spaces and rapid deployment. Its fixed ejector radial delayed blowback system cycles 9mm efficiently while keeping overall length to a trim 23.7 inches—compact enough to stash or move through structures, long enough to run the gun properly.

The build quality speaks to CMMG's attention to detail. You get a billet 6061-T6 aluminum upper and a forged 7075-T6 aluminum Mk4 lower receiver, paired with an 8-inch barrel (1:10 twist, 4140CM steel) and a CMMG ZEROED linear compensator to manage recoil and keep the dot on target. The CMMG EML4 handguard features full M-LOK real estate on both sides and the bottom, plus M-LOK between Picatinny sections—plenty of mounting options for lights, lasers, or other must-haves. The whole package runs on CMMG 9ARC magazines, the same intuitive AR mag platform you already know.

The RipBrace quick-deploy brace, ambidextrous ZEROED charging handle, and 60/90-degree safety selector give you the controls you expect. A CMMG ZEROED drop-in single-stage trigger breaks cleanly, and the carbine buffer setup keeps things running smooth. At 4.6 pounds, it's light enough for extended handling without feeling flimsy. This is a no-nonsense 9mm platform—built for shooters who value modularity, reliability, and a familiar manual of arms.

Key Features

• Fixed ejector radial delayed blowback operating system optimized for 9mm performance
• 8-inch 4140CM steel barrel with 1:10 twist for reliable cycling and accuracy
• Billet 6061-T6 upper and forged 7075-T6 lower receiver for durability
• CMMG EML4 M-LOK handguard with mounting slots on sides and bottom
• RipBrace for quick deployment and stable support
• Ambidextrous CMMG ZEROED charging handle for either-hand operation
• CMMG ZEROED drop-in single-stage trigger
• 60/90-degree safety selector
• CMMG ZEROED linear compensator to manage recoil
• Compatible with CMMG 9ARC 30-round magazines using standard AR magazine controls

Specifications

Frequently Asked Questions

What magazines does the Banshee MK4 use?

The Banshee MK4 fires from CMMG 9ARC magazines. This pistol includes one 30-round magazine and uses the same straightforward AR-15 manual of arms for loading, unloading, and magazine changes. If you're already familiar with AR platforms, the controls and magazine system will feel right at home.

Is the RipBrace included, and how does it work?

Yes, the CMMG RipBrace comes standard on this model. It's a quick-deploy brace designed to attach to the receiver extension, allowing fast setup for shooting and easy stowage. The brace provides stable support when firing and is compliant with federal law when used as a brace rather than a stock.

Can I mount a light or laser to the handguard?

Absolutely. The CMMG EML4 M-LOK handguard features extensive mounting slots on the sides and bottom, as well as M-LOK sections between Picatinny rail sections on top. You have plenty of real estate to attach the accessories that matter to your use case.

What makes the fixed ejector system different?

The Banshee MK4 uses a fixed ejector with radial delayed blowback operation, specifically tuned for 9mm cartridges. This system cycles the round reliably and ejects efficiently, all while keeping the gun balanced and controllable despite the short 8-inch barrel.