The CMMG Resolute Mk4 (brand part no. 34A120F-MB) is chambered in .338 ARC, a cartridge built to combine AR-15-platform convenience with the stopping power of a large-bore bullet, finished here in a distinctive Midnight Bronze Cerakote. It strives to emulate the sub- or supersonic versatility of the now-ubiquitous .300 Blackout cartridge while delivering more energy on target and requiring less gas system tuning when switching between suppressed and unsuppressed fire. To maximize parts compatibility, .338 ARC uses the same bolt as 6.5 Grendel AR-15s. It suits hunters and precision-minded shooters who want more downrange energy from a semi-automatic AR-pattern rifle.

Key Specifications

• Chambered in .338 ARC, a large-bore cartridge built for AR-15-platform compatibility.
• Rifling twist of 1:8 inches stabilizes .338 ARC bullet weights.
• Fitted with a 16.1-inch barrel for full-length ballistic performance.
• Ships in a 10-round capacity configuration.
• Uses the same bolt as 6.5 Grendel AR-15s for maximum parts compatibility.
• Finished in Midnight Bronze Cerakote for a distinctive look.
• Overall length measures approximately 39.7 inches.
• Ships without factory sights, ready for an optic of your choice.
• Barrel is chrome-moly steel with a black nitride finish, threaded 5/8×24.

Frequently Asked Questions

What makes .338 ARC different from .300 Blackout? It delivers more energy on target and needs less gas system tuning when switching between suppressed and unsuppressed fire.

Does this rifle share parts with other AR-15s? Yes, .338 ARC uses the same bolt as 6.5 Grendel AR-15s for easy parts compatibility.

Buy the CMMG Resolute Mk4 .338 ARC Rifle

This hard-hitting .338 ARC rifle is ready to ship. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL, and check out more CMMG rifles alongside other semi-auto rifles.