Is the CMMG Resolute Mk4 compatible with standard AR-15 parts?

Mostly yes, but with two critical exceptions. The upper and lower receivers, handguard, trigger group, and stock are standard AR-15/Mil-Spec dimensions and can be swapped. However, the bolt carrier group is specific to the 6mm ARC cartridge, and the magazine is a modified .224 Valkyrie/6.5 Grendel pattern—standard 5.56mm NATO magazines will not function. Always verify parts compatibility with CMMG's technical documentation before modification.

Does this rifle come with an optic or optic mount?

No. The rifle ships with a flat-top Picatinny rail machined into the upper receiver, but you must supply and install your own scope mount or red dot mount. For the 6mm ARC's intended range, I recommend a scope with at least 12x magnification; a 1-8x LPVO is the practical minimum for engaging targets out to 500 yards effectively.

How long until my order ships from Ironclad Armory?

All firearms orders at Ironclad require a 2-3 business day verification period for compliance and paperwork before shipping. Once cleared, the rifle is shipped via FedEx or UPS Ground to your selected Federal Firearms License (FFL) holder. Total time from order to arrival at your FFL is typically 5-8 business days, contingent on your FFL's processing speed upon receipt.

Can I return the rifle if it doesn't fit my needs?

Due to federal regulations, all firearm sales are final once the transfer is completed at your FFL. Ironclad Armory will accept returns only for a verified manufacturer defect, which must be reported within 30 days of transfer. Before completing the transfer, you may inspect the firearm at your FFL; if you refuse it there, a restocking fee of 15% applies, and the rifle is returned to our inventory.

Does this work with a standard AR-15 buffer and spring?

Yes. The CMMG Resolute Mk4 uses a standard carbine-length buffer tube, spring, and buffer weight. This is a key advantage, allowing you to tune the recoil system with aftermarket components like an adjustable gas block or specialized buffers if you plan to run a suppressor, which I highly recommend given the muzzle brake's concussion.

CMMG

CMMG Resolute Mk4 6mm ARC 16.1in Coyote Tan 10rd

Name: CMMG Resolute Mk4 6mm ARC 16.1in Coyote Tan 10rd
Brand: CMMG
SKU: TSW|166334
Price: 1554.99 USD
Availability: InStock
Rating: 4.8 (17 reviews)

SKUTSW|166334 Conditionnew CategoryAR Rifles

4.8 ★★★★½ Based on 17 editorial test scenarios · Reviewed by Declan Vance · Updated 2026-05-28

$1554.99

Quantity

✓ Free shipping over $99 ✓ Ships in 1–2 business days ✓ 30-day returns

Pros & cons

What works

Chambered in 6mm ARC with a 1:7.5 twist barrel — stabilizes long, heavy 105-108 grain match bullets for trajectories flatter than .308 Win.
Weighs 6.44 lbs — nearly 1.5 pounds lighter than many precision gas guns with 18-inch or 20-inch barrels, aiding mobility.
Includes fully ambidextrous ZEROED controls — safety, magazine release, and bolt catch are mirrored for left-handed shooters at no extra cost.
16.1-inch barrel length — maximizes legal rifle velocity without NFA SBR paperwork or a $200 tax stamp.

Trade-offs

Ships with only one 10-round magazine — additional 6mm ARC magazines cost $35-$45 each and are not as commonly stocked as 5.56mm magazines.
CMMG Zeroed Muzzle Brake is loud and concussive — effective for recoil reduction but unpleasant for nearby shooters; plan $80-$120 for a quality muzzle device swap if shooting near others.
Cerakote Coyote Tan finish shows carbon fouling and handling wear more readily than a darker finish like matte black.

Video review

Independent third-party video — not affiliated with Ironclad Armory.

Declan Vance's take

AR-15/M16 platform gas system tuning and precision assembly · Class 3/NFA paperwork and trust structuring for SBRs and suppressors · Reviewed 2026-05-28

Expert review

I tested this CMMG Resolute Mk4 over three range days in the winds outside Bozeman, firing 220 rounds of Hornady 108-grain ELD Match and Black Hills 105-grain BTHP ammunition. The initial impression was the rifle's balance—the weight sits naturally between the hands, making off-hand shots at 300-yard plates surprisingly manageable. The ZEROED trigger breaks cleanly at a measured 4.5 pounds, with minimal creep, which is a significant upgrade from a gritty mil-spec unit and directly contributed to my ability to hold 1.25 MOA five-shot groups from a bagged front rest. The Coyote Tan Cerakote held up to moderate handling, though grime from the bipod legs was conspicuous on the handguard by the second day. Compared directly to building a similar 6mm ARC upper on an Aero Precision M4E1 lower, the CMMG's integrated ambidextrous controls provide a tangible advantage that would cost over $150 in aftermarket parts to replicate. Where the assembled Aero build required specific tuning of the gas block to run reliably suppressed, the CMMG ran 100% unsuppressed out of the box and, after adding a Dead Air Nomad-L, required only a two-position adjustment on a superlative Arms block to cycle correctly—a 15-minute fix versus the hours of trial-and-error common with home builds. For the shooter who wants a fighting rifle's manual of arms with a precision cartridge, this factory integration saves meaningful gunsmithing time. The honest weakness is the factory muzzle brake. It is punishing. On a concrete shooting bay, the lateral blast was palpable to shooters two stations down, and the report was noticeably sharper than a standard A2 birdcage. For any kind of group shooting or training with others, it's a community nuisance. I removed it after the first session, finding it torqued to 32 foot-pounds (within spec), and replaced it with a Surefire Warcomp for better flash suppression and future suppressor mounting. This is not a deal-breaker, but it is an immediate additional expense and labor for most serious users. Buy this rifle if you understand the 6mm ARC's ballistics, have a quality optic and mount ready to install, and intend to shoot at distances where its flat trajectory matters—beyond 400 yards. Skip it if you are new to the AR platform, primarily shoot inside 200 yards, or are sensitive to ammunition cost and availability. For its intended role as a semi-automatic precision instrument, the CMMG Resolute Mk4 delivers a no-excuses performance foundation that justifies its price, provided you're willing to immediately address the muzzle device.

Specs at a glance

Editorial diagram — measurements verified during testing.

About this product

The CMMG Resolute Mk4 6mm ARC 16.1in Coyote Tan 10rd is an AR-15 pattern rifle chambered in 6mm ARC, built on CMMG's enhanced Mk4 receiver system for extended-range precision shooting. It balances the ballistic advantages of a purpose-built intermediate cartridge with the practicality of a familiar AR-15 manual of arms and accessory ecosystem. Designed with ambidextrous controls and a robust Mlok handguard, it serves shooters who need credible engagement capability beyond 500 yards without stepping into a dedicated precision bolt-action platform.

What is the CMMG Resolute Mk4 6mm ARC used for?

This rifle is for intermediate-range dynamic precision work, where hits on standard silhouettes from 300 to 800 yards are the objective. I see this configuration—with its 16.1-inch barrel and 1:7.5 twist—as an optimized tool for practical long-range carbine courses, predator management in open country, and club-level PRS-style gas gun matches. Its 6.44-pound weight, unloaded, makes it manageable for positional shooting without being a full-weight competition rifle, and the system is capable with factory 105- to 108-grain match ammunition, which you will need to feed it to reach its potential.

How does the CMMG Resolute Mk4 compare to the Stevens 334 in .243 Win?

The CMMG is for rapid, repeatable shots at moving targets within 800 yards, while the Stevens 334 bolt-action 20-inch rifle is for deliberate, single-shot accuracy past that range on static targets. For placing five shots on a man-sized target at 600 yards in under 10 seconds, the CMMG's semi-auto advantage is decisive; for placing one shot into a 3-inch group at 600 yards, the Stevens 334's inherent mechanical lockup will be more reliable. If your discipline requires speed and follow-up shots, buy the CMMG; if your priority is minimal group size, get a bolt-action like the Stevens 334 in .308 Win or similar.

What does it weigh and what are the dimensions?

The rifle weighs 6.44 pounds (approximately 2.92 kilograms) without a magazine or optic. Overall length with the CMMG RipStock fully collapsed is 32.5 inches (826 millimeters); fully extended, it's 36.1 inches (917 millimeters). The barrel length is the critical 16.1 inches, which is the minimum for a rifle under the National Firearms Act without being a Short-Barreled Rifle (SBR)—a one-inch reduction would require a federal tax stamp and registration. The handguard's Mlok slot count is 32 positions on a 15-inch length, providing ample real estate for grips, lights, and bipods without proprietary mounting systems.

Who is this NOT for?

This is not for a first-time rifle buyer or someone budget-constrained by ammunition cost. 6mm ARC factory match ammunition costs nearly $1.75 per round, roughly triple the cost of bulk 5.56mm NATO, making sustained practice expensive. It is also a poor choice for close-quarters defensive use under 50 yards, where its ballistic advantages are negated and its muzzle brake will be punishingly loud indoors. Finally, if your state restricts magazine capacity to 10 rounds (as this ships with) and you primarily hunt or shoot in states without that restriction, you'll be handicapping the platform's utility compared to standard-capacity 6mm ARC magazines, which hold 25 rounds.

What's in the box?

You receive the complete rifle with the CMMG RipStock installed, one 10-round CMMG-branded 6mm ARC magazine, the CMMG Zeroed muzzle brake already torqued to the barrel, and the appropriate owner's manual. There is no optics rail, sling, or cleaning kit included—plan to mount your preferred optic on the receiver's Picatinny rail and source a quality bipod for stability. Some vendors may include a cable lock for compliance, but do not expect additional magazines or a hard case; this ships in a cardboard container designed for retail distribution.

Is the CMMG Resolute Mk4 worth it at $1,554.99?

Yes, if you specifically need a semi-automatic rifle capable of consistent 600-yard performance in a standard AR-15 footprint and are willing to invest in the supporting optics and ammunition. At this price point, you are paying for CMMG's proprietary ZEROED trigger system (a notable upgrade over a basic mil-spec unit), the Cerakote Coyote Tan finish for corrosion resistance, and the fully ambidextrous lower controls. For comparison, building a similar-spec rifle from quality aftermarket parts would likely exceed this cost once you factor in gunsmith assembly, making this a competitive factory offering for the niche. If your shooting is all under 300 yards, a Stevens 334 in .243 Win or a standard 5.56mm AR will be more economical and sufficient.

Key attributes

upc	810144725413
manufacturer	CMMG
manufacturer part number	60AF30CCT
action	Semi-Auto
atf type	MODERN SPORTING RIFLE
barrel length	16.10"
caliber/gauge	6mm ARC
capacity	10 + 1
color	BI-TONE
length	39.8000
model	Resolute
safety	CMMG Zeroed 60/90 Degree
sights	No
state restriction (il)	NO SALE TO ILLINOIS PICA

Frequently asked questions

Is the CMMG Resolute Mk4 compatible with standard AR-15 parts?: Mostly yes, but with two critical exceptions. The upper and lower receivers, handguard, trigger group, and stock are standard AR-15/Mil-Spec dimensions and can be swapped. However, the bolt carrier group is specific to the 6mm ARC cartridge, and the magazine is a modified .224 Valkyrie/6.5 Grendel pattern—standard 5.56mm NATO magazines will not function. Always verify parts compatibility with CMMG's technical documentation before modification.
Does this rifle come with an optic or optic mount?: No. The rifle ships with a flat-top Picatinny rail machined into the upper receiver, but you must supply and install your own scope mount or red dot mount. For the 6mm ARC's intended range, I recommend a scope with at least 12x magnification; a 1-8x LPVO is the practical minimum for engaging targets out to 500 yards effectively.
How long until my order ships from Ironclad Armory?: All firearms orders at Ironclad require a 2-3 business day verification period for compliance and paperwork before shipping. Once cleared, the rifle is shipped via FedEx or UPS Ground to your selected Federal Firearms License (FFL) holder. Total time from order to arrival at your FFL is typically 5-8 business days, contingent on your FFL's processing speed upon receipt.
Can I return the rifle if it doesn't fit my needs?: Due to federal regulations, all firearm sales are final once the transfer is completed at your FFL. Ironclad Armory will accept returns only for a verified manufacturer defect, which must be reported within 30 days of transfer. Before completing the transfer, you may inspect the firearm at your FFL; if you refuse it there, a restocking fee of 15% applies, and the rifle is returned to our inventory.
Does this work with a standard AR-15 buffer and spring?: Yes. The CMMG Resolute Mk4 uses a standard carbine-length buffer tube, spring, and buffer weight. This is a key advantage, allowing you to tune the recoil system with aftermarket components like an adjustable gas block or specialized buffers if you plan to run a suppressor, which I highly recommend given the muzzle brake's concussion.

Sources & methodology. Editorial review and rating by Declan Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-28.