CMMG BANSHEE MK57 PISTOL 5.7X28 8 ARMOR BLK

The CMMG Banshee MK57 pistol in 5.7x28mm is a modern take on the AR-platform pistol, engineered around one of the fastest-growing defensive cartridges in the country. If you've been curious about 5.7x28mm but didn't want to sacrifice AR-15 ergonomics and controls you already know, the Banshee MK57 bridges that gap. It runs FN Five-seveN pattern magazines, accepts standard AR-15 triggers, and features familiar controls like last-round bolt hold-open—all in a compact, handy package that tips the scales at just 4.8 pounds.

What makes the 5.7x28mm appealing is its low recoil impulse and velocity that punches above its weight class at close range, especially from a shorter barrel. CMMG's MK57 platform was purpose-built for this cartridge, using a radial delayed blowback system tuned for reliable function. The 5-inch 4140CM barrel keeps the overall length to 20.9 inches, making it maneuverable in tight spaces without sacrificing capability. Every component is CMMG's own—from the billet aluminum upper and forged lower receiver to the ZEROED ambi charging handle, pistol grip, and trigger group—so you get a cohesive, well-integrated system rather than a parts-bin special.

The RipBrace gives you a solid cheek weld and support point without the tax and paperwork of a traditional stock, and the CMMG ZEROED linear compensator on the front helps tame what little recoil this round produces. M-LOK mounting on the EML4 handguard lets you add optics, lights, or other accessories as your role demands. Whether you're exploring the 5.7x28mm platform for the first time or you already run a Five-seveN and want rifle-controls compatibility, the Banshee MK57 delivers the goods.

Key Features

• 5.7x28mm platform engineered for reliability and low recoil
• Compatible with FN Five-seveN pattern magazines
• Full AR-15 ergonomics: last-round bolt hold-open, standard trigger interface, familiar controls
• 5-inch 4140CM barrel with 1:9 twist rate
• Radial delayed blowback operating system
• Billet 6061-T6 aluminum upper and forged 7075-T6 aluminum lower receiver
• CMMG ZEROED linear compensator on 1/2x28 threads
• CMMG ZEROED ambi charging handle and drop-in single-stage trigger
• M-LOK handguard for modular accessory mounting
• RipBrace for improved control and cheek weld
• Integrated trigger guard
• Lightweight at 4.8 lbs with Cerakote finish

Specifications

Frequently Asked Questions

What magazines does the CMMG Banshee MK57 use?

The Banshee MK57 is designed to use FN Five-seveN pattern magazines. It ships with a 20-round Promag.

Can I use AR-15 triggers and controls on the Banshee MK57?

Yes. The Banshee MK57 is built on an AR-compatible platform and accepts standard AR-15 triggers. It also features familiar AR controls including a last-round bolt hold-open function and a standard safety selector interface.

What is the barrel length and overall length of this pistol?

The Banshee MK57 has a 5-inch barrel and an overall length of 20.9 inches, making it compact and maneuverable while still delivering the capability of the 5.7x28mm cartridge.

What is included with the Banshee MK57?

The pistol ships with a CMMG RipBrace, one 20-round Promag magazine, CMMG ZEROED charging handle, trigger, safety, and pistol grip, plus the CMMG ZEROED linear compensator already installed on the muzzle.