CMMG 30A240ACT RESOLUTE MK4 300BO 14.5 COY

Description

CMMG 30A240ACT Resolute Mk4 .300 BLK 14.5″ Coyote — Built for Suppressed Performance

The CMMG 30A240ACT Resolute Mk4 .300 BLK 14.5 Coyote delivers a heavy-hitting .30 caliber round on target, purpose-built around subsonic loads for shorter barrel, suppressed rifles. It uses standard M4/AR15 lower parts and common ammo components, making it a practical choice for home defense and quiet shooting. This rifle is built on the Mk4 AR15 platform with an EML handguard, full-length M-LOK slots on both sides and the bottom, plus M-LOK between the top Picatinny rail sections. It includes ZEROED parts: pistol grip, drop-in trigger, 60/90-degree ambi safety, and ambi mag catch. According to CMMG specs, the 14.5-inch barrel is pinned and welded to meet 16-inch overall length requirements, keeping it legal without a tax stamp.

Manufacturer	CMMG
Model	30A240ACT Resolute Mk4
Material	7075-T6 aluminum upper and lower receiver; 4140 steel barrel (per manufacturer specs)
Compatibility	Standard AR15 lower parts; .300 BLK magazines
Finish	Coyote brown anodized; MIL-SPEC hardcoat
Weight	6 lbs 14 oz (unloaded, per manufacturer specs)
Condition	New

Key Features

• EML Handguard with Full M-LOK — Why it matters: You get uninterrupted M-LOK slots on three sides and between the top rail sections, so mounting lights, grips, or lasers is fast and secure without adding bulk.
• ZEROED Drop-In Trigger — Why it matters: CMMG’s own trigger breaks cleanly at around 4.5 pounds with minimal creep, giving you consistent shot placement for both subsonic and supersonic loads.
• 60/90-Degree Ambi Safety — Why it matters: You can switch between 60-degree and 90-degree throw to match your shooting style, and ambidextrous operation works for left- or right-handed shooters.
• Pinned and Welded 14.5-Inch Barrel — Why it matters: The 14.5-inch barrel keeps the rifle compact for home defense, while the pinned/welded muzzle device brings overall length to 16 inches, avoiding NFA hassle.
• .300 BLK Chambering — Why it matters: Subsonic rounds run reliably with a suppressor, and supersonic loads give you full .30-caliber energy out to 200 yards—all from a standard AR15 lower.

Who It’s For

This rifle is built for the shooter who wants a dedicated suppressed host for home defense or hunting varmints and hogs. It also fits the traditionalist who appreciates a solid, no-nonsense AR that runs on standard parts and doesn’t require a tax stamp. If you value a compact, accurate platform that handles both subsonic and supersonic .300 BLK without fuss, the Resolute Mk4 is your match.

Pros & Cons

• Pros: Reliable cycling with subsonic ammo; ambi controls for lefties; M-LOK handguard is easy to accessorize; pinned/welded barrel saves you $200 on a stamp; uses standard AR15 lower parts for easy repairs.
• Cons: The 14.5-inch barrel means you can’t swap muzzle devices without a gunsmith; .300 BLK ammo costs more than 5.56; the ZEROED trigger is good but not as crisp as a Geissele SSA-E.

Comparison vs. Similar Rifles

Feature	CMMG Resolute Mk4 .300 BLK	Geissele Super Duty .300 BLK	Zev Technologies Mega .300 BLK
Barrel Length	14.5″ (pinned/welded)	14.5″ (pinned/welded)	16″ (no pin/weld)
Handguard	EML M-LOK (full length)	Geissele MK16 M-LOK	Zev M-LOK
Trigger	ZEROED drop-in (~4.5 lb)	Geissele SSA-E (~3.5 lb)	Mil-spec
Weight	6 lb 14 oz	7 lb 2 oz	7 lb 8 oz
Ambi Controls	Safety + mag catch	Safety only	None
Price	$1,537.60	$1,899	$1,749

The CMMG gives you the best value for suppressed use: ambi controls, a better-than-mil trigger, and a lighter overall package. The Geissele has a superior trigger but costs $360 more. Zev’s 16-inch barrel avoids pin/weld but is heavier and lacks ambi features.

FAQ

Is the CMMG 30A240ACT Resolute Mk4 .300 BLK 14.5 Coyote legal without a tax stamp?

Yes. The 14.5-inch barrel has a pinned and welded muzzle device that brings the overall length to 16 inches, meeting ATF rifle requirements. You can buy it as a standard rifle without a tax stamp.

Does this rifle cycle subsonic .300 BLK reliably?

Yes. CMMG designed the gas system for subsonic loads. With a suppressor attached, it cycles subsonic ammo reliably. Without a suppressor, you may need supersonic rounds for consistent function.

What magazines work with this rifle?

Standard AR15 magazines work, but you should use .300 BLK-specific magazines (like Lancer L7AWM .300 BLK or Magpul PMAG .300 BLK) for best feeding with the wider .30-caliber round.

Can I swap the handguard or muzzle device?

You can replace the handguard with any AR15 free-float model. The muzzle device is pinned and welded, so swapping it requires a gunsmith to remove the pin and weld a new one.

Why Buy From Us

• ✓ Nationwide delivery (all 50 states)
• ✓ Ships 1-2 business days
• ✓ 30-day returns
• ✓ Secure checkout

Last updated: April 2026

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