$1,397.69
Availability: In Stock
The CMMG Banshee MK57 5.7x28mm AR pistol with 8-inch barrel is purpose-built for shooters who want modern personal defense firepower in a compact, highly maneuverable platform. This isn't a rifle dressed down—it's a radial delayed blowback system engineered from the ground up around the 5.7x28mm cartridge, a round that pairs flat trajectory with reduced recoil and barrier-blind terminal performance. The 8-inch barrel maximizes velocity and energy from the round at close quarters where most defensive encounters occur. At just 4.8 pounds and 23.7 inches overall length, the Banshee MK57 fits tight spaces—vehicles, bags, home defense corners—without sacrificing shootability or control.
CMMG's Mk57 platform accepts standard FN Five-seveN pattern magazines, including the included 20-round Promag, so ammo and spares are straightforward. The gun handles like an AR pistol should: you get last-round bolt hold-open, an oversized mag release that works with gloved hands, and an ambidextrous charging handle. The CMMG ZEROED drop-in trigger, 60/90-degree safety selector, and integrated trigger guard keep the controls intuitive and accessible. Billet 6061-T6 aluminum upper and forged 7075-T6 aluminum lower receivers are tied together with a pistol-tube buffer system—lighter and faster than full-size carbine setups but still reliable.
The EML7 M-LOK handguard wraps the barrel with full-length slots on both sides, bottom, and between top picatinny sections, giving you room for lights, lasers, slings, and backup sights without compromise. The factory CMMG ZEROED linear compensator (1/2x28 thread) tames what little recoil the round generates. All of this comes finished in Extended Armor Black Cerakote—a professional, durable coating that resists wear and corrosion. Whether you're building a truck gun, a home-defense rapid-response tool, or an ultra-short-range specialist, the Banshee MK57 delivers modern AR ergonomics and reliability in a package that goes where full-size rifles cannot.
| Caliber | 5.7x28mm |
| Barrel Length | 8 inches |
| Barrel Contour | MT |
| Barrel Material | 4140CM SBN |
| Barrel Twist | 1:9 |
| Operating System | Radial Delayed Blowback |
| Muzzle Device | CMMG ZEROED Linear Compensator |
| Muzzle Thread | 1/2 x 28 |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Lower Receiver | Mk57 Forged 7075 T6 Aluminum |
| Handguard | CMMG EML7 M-LOK |
| Charging Handle | CMMG ZEROED Ambi |
| Trigger | CMMG ZEROED Drop-In |
| Trigger Guard | Integrated |
| Safety Selector | CMMG ZEROED 60/90 Degree |
| Pistol Grip | CMMG ZEROED |
| Buffer Type | Carbine |
| Receiver Extension | Pistol Tube |
| Magazine Included | 20-round Promag |
| Magazine Compatibility | FN Five-seveN pattern |
| Weight | 4.8 lbs |
| Overall Length | 23.7 inches |
| Platform | CMMG Mk57 |
| Finish | Extended Armor Black Cerakote |
The Banshee MK57 accepts FN Five-seveN pattern magazines. It comes with a 20-round Promag, and you can source additional 5.7x28mm magazines from FN and other manufacturers that produce magazines for the Five-seveN platform.
The Banshee MK57 is an AR pistol platform. It features a pistol tube buffer system and is configured as a pistol. Consult local and federal law regarding SBR registration requirements and definitions if you plan to add a stabilizing brace or other components; laws vary by jurisdiction.
The Banshee MK57 comes with one 20-round Promag magazine. No other accessories or optics are included.
The 5.7x28mm is a modern personal defense cartridge known for reduced recoil, flat trajectory at close range, and barrier-blind performance. It pairs well with the compact Banshee platform for defensive, tactical, or sport applications. Ammunition availability and performance vary by load; consult ballistic data and manufacturer specifications for the specific ammunition you choose.
SKU: 120922874 • Weight: 7oz
Availability: In Stock
The CMMG Banshee MK57 5.7x28mm AR pistol with 8-inch barrel is purpose-built for shooters who want modern personal defense firepower in a compact, highly maneuverable platform. This isn't a rifle dressed down—it's a radial delayed blowback system engineered from the ground up around the 5.7x28mm cartridge, a round that pairs flat trajectory with reduced recoil and barrier-blind terminal performance. The 8-inch barrel maximizes velocity and energy from the round at close quarters where most defensive encounters occur. At just 4.8 pounds and 23.7 inches overall length, the Banshee MK57 fits tight spaces—vehicles, bags, home defense corners—without sacrificing shootability or control.
CMMG's Mk57 platform accepts standard FN Five-seveN pattern magazines, including the included 20-round Promag, so ammo and spares are straightforward. The gun handles like an AR pistol should: you get last-round bolt hold-open, an oversized mag release that works with gloved hands, and an ambidextrous charging handle. The CMMG ZEROED drop-in trigger, 60/90-degree safety selector, and integrated trigger guard keep the controls intuitive and accessible. Billet 6061-T6 aluminum upper and forged 7075-T6 aluminum lower receivers are tied together with a pistol-tube buffer system—lighter and faster than full-size carbine setups but still reliable.
The EML7 M-LOK handguard wraps the barrel with full-length slots on both sides, bottom, and between top picatinny sections, giving you room for lights, lasers, slings, and backup sights without compromise. The factory CMMG ZEROED linear compensator (1/2x28 thread) tames what little recoil the round generates. All of this comes finished in Extended Armor Black Cerakote—a professional, durable coating that resists wear and corrosion. Whether you're building a truck gun, a home-defense rapid-response tool, or an ultra-short-range specialist, the Banshee MK57 delivers modern AR ergonomics and reliability in a package that goes where full-size rifles cannot.
| Caliber | 5.7x28mm |
| Barrel Length | 8 inches |
| Barrel Contour | MT |
| Barrel Material | 4140CM SBN |
| Barrel Twist | 1:9 |
| Operating System | Radial Delayed Blowback |
| Muzzle Device | CMMG ZEROED Linear Compensator |
| Muzzle Thread | 1/2 x 28 |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Lower Receiver | Mk57 Forged 7075 T6 Aluminum |
| Handguard | CMMG EML7 M-LOK |
| Charging Handle | CMMG ZEROED Ambi |
| Trigger | CMMG ZEROED Drop-In |
| Trigger Guard | Integrated |
| Safety Selector | CMMG ZEROED 60/90 Degree |
| Pistol Grip | CMMG ZEROED |
| Buffer Type | Carbine |
| Receiver Extension | Pistol Tube |
| Magazine Included | 20-round Promag |
| Magazine Compatibility | FN Five-seveN pattern |
| Weight | 4.8 lbs |
| Overall Length | 23.7 inches |
| Platform | CMMG Mk57 |
| Finish | Extended Armor Black Cerakote |
The Banshee MK57 accepts FN Five-seveN pattern magazines. It comes with a 20-round Promag, and you can source additional 5.7x28mm magazines from FN and other manufacturers that produce magazines for the Five-seveN platform.
The Banshee MK57 is an AR pistol platform. It features a pistol tube buffer system and is configured as a pistol. Consult local and federal law regarding SBR registration requirements and definitions if you plan to add a stabilizing brace or other components; laws vary by jurisdiction.
The Banshee MK57 comes with one 20-round Promag magazine. No other accessories or optics are included.
The 5.7x28mm is a modern personal defense cartridge known for reduced recoil, flat trajectory at close range, and barrier-blind performance. It pairs well with the compact Banshee platform for defensive, tactical, or sport applications. Ammunition availability and performance vary by load; consult ballistic data and manufacturer specifications for the specific ammunition you choose.
SKU: 120922874 • Weight: 7oz