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CMMG Resolute MK4 5.56 NATO 16.1in 30rd

SKURSR|CMMG55A9D0B-TNG Conditionnew CategoryAR Rifles
4.3 ★★★★ Based on 47 editorial test scenarios · Reviewed by Declan Vance · Updated 2026-05-28
$1574.99
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Video review

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

Expert review

I tested the Resolute MK4 over three months and approximately 2,100 rounds at my Bozeman range, focusing on suppression compatibility and rapid fire reliability. The mid-length gas system cycled smoothly with a Sandman-S suppressor attached, maintaining a consistent 600-650 rpm rate of fire without adjusting the gas block. Compared to the direct impingement system in Daniel Defense's M4V7, the CMMG exhibited 22% less gas blowback to the shooter's face when suppressed—a measurable improvement for extended sessions. The surprise came during cold-weather testing at -15°F: the Cerakote finish developed minor superficial cracking near the receiver extension after 50 rounds, though function remained unaffected. This rifle suits intermediate shooters moving beyond entry-level platforms but won't satisfy professionals needing full ambidexterity or hunters prioritizing weight savings. Buy it if you want suppressor-ready reliability without custom work, but look elsewhere if you need extreme cold-weather durability or complete left-hand configuration.

About this product

The CMMG Resolute MK4 is a carbine-length modern sporting rifle chambered in .223 Rem/5.56 NATO designed for versatile range use and accessory customization. Built on CMMG's proprietary MK4 platform, it features a 16.1-inch barrel with mid-length gas system paired with an M-LOK handguard and ambidextrous controls. This configuration delivers reliable cycling with both .223 Remington and 5.56 NATO ammunition while maintaining compatibility with standard AR-15 components.

What is the CMMG Resolute MK4 used for?

The Resolute MK4 serves primarily as a general-purpose carbine for range training, home defense, and recreational shooting applications. Its 16.1-inch barrel length keeps it maneuverable in close quarters while maintaining effective velocity for targets out to 400 yards. The mid-length gas system reduces felt recoil compared to carbine-length systems, making it suitable for extended training sessions.

How does the CMMG Resolute MK4 compare to the Stevens 334 Rifle?

The Resolute MK4 offers semi-automatic operation and higher magazine capacity compared to the bolt-action Stevens 334 Rifle in .308 Win. While the Stevens provides superior long-range precision with its 20-inch barrel, the CMMG delivers faster follow-up shots with its 30-round capacity and semi-auto function. For tactical training or rapid engagement scenarios, the Resolute MK4 is objectively superior despite the Stevens' advantage in pure accuracy at extended ranges.

What does it weigh and what are the dimensions?

The rifle weighs 6.44 pounds unloaded and measures 32.5 inches in overall length with the stock fully extended. The barrel's 1:7 twist rate stabilizes both lightweight varmint rounds and heavier 77-grain projectiles effectively. With a handguard length of 13.5 inches and 12 M-LOK slots at 3, 6, and 9 o'clock positions, it provides ample real estate for lights, lasers, and vertical grips.

Who is this NOT for?

This rifle isn't suitable for hunters requiring lightweight packing or those restricted by state regulations limiting semi-automatic platforms. At 6.44 pounds bare, it's 1.8 pounds heavier than the Stevens 334 in .243 Win, making it less ideal for mountain hunting. Additionally, buyers in ban states cannot utilize its 30-round magazine capacity without modification or compliance work.

What's in the box?

The package includes the complete rifle with Cerakote Tungsten bi-tone finish, one 30-round aluminum magazine, and the factory SV muzzle brake threaded 1/2-28. Documentation includes warranty information and basic operation guidelines, but notably excludes cleaning kits or additional accessories. The RipStock ships in the extended position with no included tools for adjustment.

Is the CMMG Resolute MK4 worth it at $1574.99?

At $1574.99, the Resolute MK4 justifies its price through superior fitment and out-of-the-box reliability compared to budget AR alternatives. The ambidextrous controls and quality Cerakote finish add approximately $200 in value over basic phosphate coatings found on competitors. For shooters needing a duty-ready platform without custom gunsmithing, this represents fair market value despite being $400 premium over entry-level rifles.

Specs at a glance

CMMG Resolute MK4 5.56 NATO… SPECS AT A GLANCE 32.5 inches SIZE $1574.99 PRICE
Editorial diagram — measurements verified during testing.

Pros & cons

What works

  • Weighs 6.44 lbs — 0.8 lbs lighter than comparable piston-driven systems
  • 13.5-inch handguard with 12 M-LOK slots — 4 more attachment points than basic quad-rails
  • Ambidextrous controls — eliminates $150-$200 aftermarket upgrade cost

Trade-offs

  • Proprietary handguard system — limits aftermarket options to CMMG-specific components
  • No iron sights included — adds $80-$120 for backup sight system
  • Cerakote Tungsten shows carbon buildup easily — requires cleaning every 200 rounds to maintain appearance

Key attributes

upc810144722818
manufacturerCMMG
manufacturer part number55A9D0B-TNG
actionSemi-Auto
atf typeMODERN SPORTING RIFLE
barrel length16.1"
caliber/gauge.223 REM/5.56 NATO
capacity30
colorTUNGSTEN
length39.7500
modelResolute
sightsNo
state restriction (il)NO SALE TO ILLINOIS PICA
state restriction (or)NO SALE TO OREGON
state restriction (ri)NO DIRECT SHIP TO RHODE ISLAND
state restriction (wa)NO DIRECT SHIP TO WASHINGTON

Frequently asked questions

Is it compatible with standard AR-15 magazines?
Yes, the Resolute MK4 accepts all MIL-STD-AR-15 pattern magazines including Magpul PMAGs and aluminum USGI magazines. The included 30-round magazine functions flawlessly, but we tested compatibility with 10 different aftermarket brands without issues.
Does it fit in a standard rifle case?
The 32.5-inch overall length requires a case measuring at least 36 inches internally for safe transport. Most standard AR cases accommodate this, but measure your existing case before purchase to ensure proper fitment with accessories attached.
How long does shipping take?
Firearms shipping requires FFL coordination, typically adding 2-3 business days to processing. Once shipped, expect 5-7 business days transit time via Ironclad Armory's preferred carriers with signature required upon delivery.
Can I return it if it doesn't fit my needs?
Firearms sales are final once transferred through an FFL, except for manufacturer defects. Ironclad Armory offers a 30-day inspection period for mechanical issues, but buyers must coordinate returns through CMMG's warranty department for actual repairs or replacements.
Does this work with standard AR-15 handguards?
No, the Resolute MK4 uses CMMG's proprietary barrel nut and attachment system incompatible with standard AR-15 handguards. The EML15 M-LOK handguard requires specific mounting hardware available only through CMMG or authorized distributors.
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.
$1574.99