The CMMG Banshee Mk57 (part no. PE-57A889D-AB) is a 5.7x28mm AR pistol built on CMMG’s Mk57 platform, designed to squeeze the full potential out of the 5.7x28mm cartridge from an 8-inch barrel. It’s a compact, close-range personal defense option that keeps familiar AR manual-of-arms while running FN Five-seveN pattern magazines, making it a versatile companion piece for shooters already invested in that magazine ecosystem.

Key Specifications

• Chambered in 5.7x28mm, a fast, flat-shooting personal defense caliber.
• Features an 8-inch barrel built to maximize 5.7x28mm velocity in a compact platform.
• Built on the Mk57 platform, CMMG’s dedicated 5.7x28mm AR system.
• Accepts FN Five-seveN pattern magazines for broad magazine compatibility.
• Features an oversized magazine release for faster, easier reloads.
• Retains standard AR-15 last-round bolt hold-open function despite the pistol-magazine feed.

Frequently Asked Questions

What caliber is the Banshee Mk57 chambered in? 5.7x28mm.

What magazines does it use? FN Five-seveN pattern magazines.

Does it hold the bolt open on the last round? Yes, it retains standard AR-15 bolt hold-open function.

Buy the CMMG Banshee Mk57 5.7x28mm Pistol

A compact, fast-handling personal defense pistol, the CMMG Banshee Mk57 is a standout in our AR pistols lineup. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL.