CMMG 30AE70ACT RESOLUTE MK4 300BO 16.1 COY

Description

The CMMG 30AE70ACT RESOLUTE MK4 300BO 16.1 COY is a factory-built .300 Blackout rifle that delivers a heavy-hitting .30 caliber round on target, originally designed around subsonic performance for suppressed use in shorter barrels. Built on the Mk4 AR15 platform, it uses standard M4/AR15 parts and ammo components, making it a practical choice for home defense and suppressed shooting. This model features a 16.1-inch barrel, EML handguard with full-length M-LOK slots on both sides and bottom, and 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. Priced at $1,537.60, it is a solid, no-nonsense rifle for traditional shooters who value reliability and craftsmanship.

Specification	Detail
Manufacturer	CMMG
Model	30AE70ACT RESOLUTE MK4 300BO 16.1 COY
Material	7075-T6 aluminum upper/lower receiver, steel barrel (per manufacturer specs)
Compatibility	Standard AR15 lower parts, .300 BLK magazines
Finish	Coyote tan anodized
Weight	6.8 lbs (unloaded, per manufacturer specs)
Condition	New

Key Features

• EML Handguard with Full M-LOK — M-LOK slots on both sides and bottom plus between top Picatinny sections allow you to mount lights, grips, and bipods exactly where you need them, without extra rail weight.
• ZEROED Drop-In Trigger — A crisp, clean break improves accuracy shot after shot, especially when shooting subsonic .300 BLK at closer ranges.
• 60/90 Degree Ambi Safety — Lets you switch between 60- and 90-degree throw angles, so you can run it with standard or high-rise optics without interference.
• Ambi Mag Catch — Speeds up reloads from either shoulder, a real advantage in defensive or competition scenarios.
• 16.1-Inch Barrel — Balances maneuverability with enough length to stabilize both supersonic and subsonic loads, giving you versatility without a tax stamp.

Who It’s For

This rifle is for the shooter who wants a dedicated .300 BLK platform that runs right out of the box. It suits homeowners looking for a reliable home defense carbine, suppressors owners who need a subsonic host, and traditionalists who appreciate a forged receiver and a clean, factory fit. It also fits the handloader who wants to experiment with cast bullets or powder charges in a proven system.

Pros & Cons

Pros: Factory-built reliability with CMMG’s warranty; ambi controls for lefties or weak-hand use; M-LOK handguard is light and strong; uses standard AR15 magazines with .300 BLK; drop-in trigger is a nice upgrade over mil-spec.

Cons: The 16.1-inch barrel is slightly longer than ideal for maximum subsonic performance (a 10-12 inch barrel is more common for suppressed use); the coyote tan finish may not match all aftermarket parts; the price point is higher than entry-level .300 BLK rifles from other brands.

Comparison

Feature	CMMG 30AE70ACT RESOLUTE	Geissele Super Duty 300 BLK	Zev Technologies OZ9C 300 BLK
Barrel Length	16.1 inches	16 inches	16 inches
Handguard	EML M-LOK (full length)	Geissele MK16 M-LOK	Zev M-LOK
Trigger	ZEROED drop-in	Geissele Super Semi-Automatic	Zev adjustable
Ambi Controls	Safety, mag catch, bolt release	Safety, bolt release	Safety, mag catch
Weight	6.8 lbs	6.9 lbs	7.1 lbs
Price	$1,537.60	$1,899.00	$1,799.00

The CMMG offers a better value for the money with full ambi controls and a drop-in trigger, while the Geissele and Zev models cost more and lack some ambi features out of the box.

FAQ

Is this rifle accurate with subsonic .300 BLK ammunition?

Yes. The 16.1-inch barrel provides enough dwell time to stabilize heavier 200-220 grain subsonic loads. Many shooters report 1.5-2 MOA accuracy with quality ammunition from brands like Hornady or Sig. The ZEROED trigger helps you get the most out of it.

Can I use standard AR15 magazines with this rifle?

Yes. The .300 BLK round uses the same magazine body as 5.56 NATO, but you should use magazines specifically marked for .300 BLK to avoid confusion. CMMG recommends Magpul PMAGs in 300 BLK configuration for reliable feeding.

Does this model come with a muzzle device for suppressor attachment?

It comes with a standard A2-style flash hider. It is not a QD mount, but you can replace it with your preferred suppressor mount. The 16.1-inch barrel is threaded 5/8×24, which is standard for .30 caliber muzzle devices.

What is the warranty on this rifle?

CMMG offers a limited lifetime warranty on the receiver and barrel, and a one-year warranty on all other parts. This covers defects in materials and workmanship, but not wear items like springs or firing pins. According to CMMG specs, they stand behind their builds.

Trust & Delivery

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

Last updated: April 2026

See also: AR Rifles | 300 Blackout Rifles | Complete Uppers