Description

The CMMG Resolute MK4 in 5.7x28mm is a semi-automatic rifle built on CMMG’s MK4 platform — an AR-style receiver architecture sized around the 5.7x28mm cartridge. The 5.7x28mm chambering is a pistol-originated cartridge originally developed for the FN Five-seveN and P90, producing muzzle velocities in the 1,700–1,900 fps range from a 16″ barrel and generating minimal felt recoil relative to rifle cartridges. The 40-round magazine capacity supports extended range sessions and training drills without frequent reloads.

The Resolute series sits in CMMG’s mid-tier lineup, offering a factory-complete rifle configuration without requiring additional components. The 16.1″ barrel keeps the rifle in non-NFA territory while providing sufficient dwell time for reliable semi-automatic cycling of the 5.7x28mm cartridge. The black finish provides a standard, low-profile appearance. Optics and accessories can be mounted via the rifle’s Picatinny/MIL-STD-1913 rail interface; specific handguard model, magazine designation, and compatible optics mount configurations should be verified against the live CMMG spec sheet before publishing. As with all serialized firearms, this rifle must transfer through a licensed FFL dealer in accordance with federal, state, and local law.

Key Features

• Firearm Type: Semi-Automatic Rifle
• Action: Semi-Auto
• Caliber: 5.7x28mm
• Capacity: 40 rounds
• Barrel Length: 16.1″
• Twist Rate: Not specified — verify against manufacturer spec sheet before publishing (CMMG 5.7x28mm Resolute MK4 typically 1:9″; confirm)
• Weight (Unloaded): Not specified
• Threaded Barrel: Not specified — must be confirmed as Yes or No before publishing
• Country of Manufacture: United States

Use Case

• 16.1″ barrel keeps the rifle legally non-NFA while providing adequate dwell time for reliable 5.7x28mm cycling
• 40-round magazine capacity supports extended range sessions and training drills without frequent reloads
• 5.7x28mm chambering produces muzzle velocities in the 1,700–1,900 fps range from a 16″ barrel, generating minimal felt recoil relative to rifle cartridges
• AR-platform MK4 architecture allows use of standard AR-compatible accessories, furniture, and optics mounting systems
• Factory-complete configuration requires no additional components for immediate use out of the box

Compliance & Legal Notes

• FFL Transfer Required: This firearm must ship to a licensed Federal Firearms Licensee (FFL) and will be transferred to the buyer in accordance with federal, state, and local law.
• Shipping Restrictions Apply: Some jurisdictions restrict or prohibit certain firearms or features. Orders may be modified or canceled if delivery is not legally permitted.
• Buyer Responsibility: The buyer is responsible for ensuring this firearm is legal to purchase, possess, and transfer in their jurisdiction.

Box / Package Contains

• One factory-new CMMG Resolute MK4 rifle in 5.7x28mm
• One 40-round magazine
• Manufacturer lock
• Owner’s manual