CMMG Resolute Mk57 5.7x28mm Rifle - 16.1" Barrel, Armor Black Finish

The CMMG Resolute Mk57 5.7x28mm rifle brings a unique platform to shooters who want the ballistic reach of a carbine without the bulk and recoil of traditional centerfire rifles. Built on CMMG's Mk57 platform, this 16.1" barrel rifle is purpose-built around 5.7x28mm—a cartridge that's gained serious traction among shooters seeking minimal recoil, fast handling, and genuine stopping power at close to intermediate ranges. What sets the Resolute apart is its ability to run FN Five-seveN pistol magazines, meaning you can share ammunition and mags between your handgun and rifle. That's practical logistics in the field or at the range.

The Resolute Mk57 splits the difference where other guns can't. It delivers better ballistics and sight radius than an SBR or compact pistol, yet remains nimble and fast-handling in tight spaces or from a vehicle. The radial delayed blowback operating system cycles the 5.7x28mm round cleanly while keeping felt recoil low—ideal if you're training hard or running multiple stages. At 6.2 lbs fully configured, it won't wear you out on a long day, and the 32.5" overall length keeps it packable for truck guns, overlanding, or cabin defense.

CMMG equipped this rifle with their ZEROED parts ecosystem: an ambidextrous charging handle, ambi safety selector, and drop-in trigger group all tuned to work together. The EML15 M-LOK handguard gives you mounting points at the cardinal positions (12, 3, 6, 9 o'clock) without unnecessary bulk—you get the accessory real estate you need and nothing extra. The RipStock provides a solid cheek weld and quick length-of-pull adjustments, and the 6-position receiver extension with ambi sling plate means lefties and righties both get a functional setup out of the box. Armor Black Cerakote finish protects against the elements, and the 1:9 twist 4140CM barrel is built to last.

This is a rifle for shooters who think beyond the obvious—people who understand that the "best" platform depends on your mission. The Resolute Mk57 excels when you need speed, low recoil, and compatibility with your duty or defensive handgun, all in a form factor that goes where other rifles can't.

Key Features

• Mk57 platform accepts FN Five-seveN style magazines—share ammo and mags with your pistol
• Radial delayed blowback operating system for reliable cycling and minimal recoil
• 16.1" 4140CM barrel with 1:9 twist and CMMG ZEROED muzzle brake
• Billet 6061 T6 aluminum upper, forged 7075 T6 lower for durability
• EML15 M-LOK handguard with mounting points at 12, 3, 6, and 9 o'clock
• ZEROED ambi charging handle, ambi safety selector (60/90°), drop-in trigger group
• RipStock with integrated sling plate for quick length-of-pull adjustment
• Lightweight at 6.2 lbs; compact at 32.5" overall length
• Armor Black Cerakote finish

Specifications

Frequently Asked Questions

Can I use FN Five-seveN pistol magazines in the Mk57?

Yes. The Mk57 platform is designed to accept FN Five-seveN style magazines without compromising AR-pattern functionality. The rifle ships with a 20-round Promag and offers last-round bolt hold open—a feature not always available in other 5.7x28mm platforms.

What is 5.7x28mm good for?

5.7x28mm is a fast, lightweight round that delivers excellent penetration at short to intermediate ranges with minimal recoil. It's favored by shooters who want lower felt recoil and faster follow-ups than traditional rifle cartridges, while gaining better ballistics and distance capability than a pistol. The Resolute Mk57's 16.1" barrel optimizes the cartridge's potential.

Is the Mk57 ambidextrous?

Yes. The rifle features an ambidextrous charging handle, an ambi safety selector (switchable between 60° and 90° throw), and an ambi sling attachment point on the receiver extension. This makes it equally capable for left- and right-handed shooters.

What's included with the Resolute Mk57?

The rifle ships as a complete rifle with a 20-round Promag magazine and is fitted with CMMG's ZEROED component suite, including the drop-in trigger group, muzzle brake, charging handle, and RipStock stock. No assembly required.