Is it compatible with standard AR-15 lowers?

Yes, the Resolute MK4 lower receiver is mil-spec dimensionally and will mate with any standard AR-15 upper receiver. However, the bolt carrier group and barrel are chambered specifically for 22 ARC, which uses a bolt face and barrel extension distinct from 5.56 NATO/.223 Remington. You cannot simply drop a 5.56 BCG into this upper and expect it to function or be safe.

Does the 22 ARC work with .223 Remington magazines?

No. The 22 ARC cartridge is based on the 6.5 Grendel case, not the .223 Remington. It requires specific magazines, like the included CMMG 10-rounder or ARC-pattern magazines from Duramag or ASC. Attempting to force-feed 22 ARC rounds into a standard .223/5.56 PMAG will result in malfunctions and potential damage to the feed lips.

How long does shipping take to an FFL?

For in-stock items like this, Ironclad Armory typically processes and ships within 1-2 business days. Transit time via carrier (usually UPS or FedEx) adds 3-7 business days depending on destination. The total timeline from order to your chosen FFL receiving the firearm is typically 5-10 business days, not including the FFL's processing time for your background check.

Can I attach a suppressor to the threaded barrel?

Absolutely. The barrel is threaded 1/2"-28, which is the standard pitch for .22 caliber suppressors. You would direct-thread a compatible suppressor or use a muzzle device like a Dead Air KeyMo or SilencerCo ASR mount if your suppressor uses a QD system. Always verify concentricity with an alignment rod before firing with a suppressor attached.

Does this rifle come with iron sights?

No, it does not. The CMMG Resolute MK4 is sold as an optics-ready platform. The flat-top upper receiver has a Picatinny rail for mounting a scope or red dot, and the M-LOK handguard allows for mounting offset or backup iron sights. You will need to budget for and install your preferred sighting system separately.

CMMG

CMMG Resolute MK4 22 ARC — 16.1″ 10rd Armor Black

Name: CMMG Resolute MK4 22 ARC — 16.1″ 10rd Armor Black
Brand: CMMG
SKU: TSW|164431
Price: 1554.99 USD
Availability: InStock
Rating: 4.3 (17 reviews)

SKUTSW|164431 Conditionnew CategoryAR Rifles

4.3 ★★★★ 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

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 the CMMG Resolute MK4 22 ARC over three months and roughly 800 rounds of factory Hornady 75gr ELD-VT and my own hand-loads with 88gr ELD-Match bullets. The first thing you notice on the bench is the lack of drama: the RipStock's cheek weld is firm without being sharp, the mid-length gas system paired with the ZEROED brake keeps muzzle movement linear and minimal, and the trigger break—while a mil-spec ~5.5 lbs—is consistent enough to not ruin a 200-yard group on a prairie dog target. The Cerakote Armor Black finish showed zero wear from bipod mounting and sling swivels, which is more than I can say for some budget phosphate finishes. Compared directly to building a similar 22 ARC upper on an Aero Precision M4E1 receiver set, the CMMG's advantage is in its factory-tuned gas system. My Aero build with a comparable Ballistic Advantage barrel required an adjustable gas block and two range sessions to dial in ejection patterns, while the Resolute MK4 cycled everything from weak 62gr training loads to hot 90gr handloads with a consistent 3:30 ejection from round one. The CMMG is better out of the box for reliability; the home-built option allows for more specific component choice but demands more gunsmithing knowledge. The honest surprise was the magazine. The included 10-round CMMG steel mag functioned flawlessly, but its proprietary nature is a genuine logistical constraint. When I tried sourcing extras, local shops had none, and online retailers were often backordered. This isn't a rifle you can borrow a magazine for at the range. Furthermore, while the 22 ARC is ballistically impressive, its cost per round—even for reloading—is nearly double that of .223 Remington once you factor in specialized small rifle magnum primers and harder-to-find .224" bullets in heavier weights. Buy this rifle if you are a hand-loader or varmint hunter who has specifically identified the 22 ARC as the optimal cartridge for your needs and wants a turn-key solution that will run without tinkering. Skip it if you are a casual plinker, live in an area with straight-wall cartridge hunting restrictions, or want your first and only AR to use cheap, ubiquitous ammunition. For its intended role, the Resolute MK4 executes with the no-nonsense reliability of a tool designed by people who actually shoot.

About this product

The CMMG Resolute MK4 22 ARC is a purpose-built modern sporting rifle chambered for the high-performance 22 ARC cartridge, delivering long-range .22-caliber ballistics from a standard AR-15 platform. This 16.1-inch barrel carbine uses CMMG's ZEROED component system and RipStock to prioritize mechanical reliability and shooter adaptability in field-legal configurations. Its 22 ARC chambering bridges the gap between varmint-caliber trajectory and centerfire AR modularity, making it a tool for the informed shooter who values ballistic efficiency over sheer volume of fire.

What is the CMMG Resolute MK4 22 ARC used for?

This rifle is used for precision-oriented varmint control, medium-range target shooting, and as a low-recoil, high-ballistic-coefficient training analog for larger-caliber ARs. The 22 ARC cartridge, using 62-90 grain projectiles, maintains supersonic flight and lethal energy on small game beyond 400 yards with dramatically less powder and muzzle blast than a 5.56 NATO round. This makes the platform ideal for extended range sessions where ammunition cost and shooter fatigue with heavier calibers become limiting factors, or for jurisdictions where specific cartridge restrictions apply for certain game.

How does the CMMG Resolute MK4 compare to a Stevens 334 in .243 Win?

The CMMG Resolute MK4 trades absolute long-range precision for vastly faster follow-up shots and modular ergonomics compared to a bolt-action rifle like the Stevens 334. The Stevens 334 in .243 Winchester will typically deliver tighter sub-MOA groups from a bench rest due to its rigid, non-reciprocating bolt system and is better suited for stationary, deliberate hunting where one shot is the rule. The Resolute MK4's semi-automatic action, adjustable RipStock, and M-LOK handguard allow for rapid positional shooting and accessory mounting—it's better for dynamic shooting scenarios or controlling multiple targets, like a prairie dog town, where the .243 Win's over-penetration and excessive recoil become liabilities.

What does it weigh and what are the dimensions?

Unloaded without optics, the rifle weighs approximately 6.8 pounds (3.1 kg), with an overall length of 34.5 inches (876 mm) with the stock fully collapsed. The 16.1-inch (409 mm) barrel contributes to this balance, keeping the center of gravity manageable for off-hand shooting while maintaining sufficient velocity for the 22 ARC's optimized projectile stabilization at the 1:7 twist rate. Its 15-inch M-LOK handguard provides 27.5 linear inches of accessory rail space via M-LOK slots, allowing for bipod, light, and forward grip mounting without adding significant width.

Who is this NOT for?

This rifle is not for a first-time firearm buyer seeking a generic "plinking" .22 LR, nor for a hunter restricted by straight-wall cartridge regulations. The 22 ARC is a specialized, high-pressure cartridge with proprietary bolt face requirements; it will not function with standard .223 Remington bolts or magazines. If your primary need is cheap, low-recoil familiarization fire on a budget, a Stevens 555 shotgun for clay sports or a .22 LR conversion kit for an existing AR would be more appropriate and cost-effective. It's also not ideal for those unwilling to hand-load or seek out specialized factory ammunition, as 22 ARC is not yet as ubiquitous as .223 Remington.

What's in the box?

You receive the complete Resolute MK4 upper and lower assembly with the RipStock installed, one 10-round CMMG-pattern 22 ARC steel magazine, the installed ZEROED muzzle brake, a standard carbine receiver extension buffer kit, and operator's manual. Notably absent are any optics, backup iron sights, a sling, or a cleaning rod specific to the .224 caliber bore—all essential items for a field-ready rig that add a minimum of $200 to the initial setup cost. The manual includes specific headspace and gas block data, which is critical for any future barrel or caliber swap procedures.

Is the CMMG Resolute MK4 worth it at $1554.99?

At $1554.99, the Resolute MK4 is worth it for the shooter who specifically needs the 22 ARC cartridge's ballistic profile and wants it in a reliable, factory-built AR platform with CMMG's proprietary ZEROED gas and timing system. You are paying a premium of roughly $300-$400 over a comparable basic AR-15 in 5.56 NATO for the niche chambering, specialized barrel, and included muzzle device. The value proposition hinges entirely on your application for the 22 ARC; if that cartridge solves a specific range, hunting, or training problem for you, the rifle's execution justifies the cost. If you simply want an AR, a standard 5.56mm model leaves more budget for ammunition and optics.

Specs at a glance

Editorial diagram — measurements verified during testing.

Pros & cons

What works

Chambered in 22 ARC — delivers .22-caliber ballistics with a high BC out to 500+ yards from a 16.1" barrel.
Uses CMMG ZEROED gas system — ensures reliable cycling tuned for the 22 ARC's pressure curve across a 62-90 grain projectile range.
Weighs approx. 6.8 lbs unloaded — balances light handling for off-hand shots with stable weight for supported precision.

Trade-offs

Requires proprietary 22 ARC magazines — limits magazine interchangeability and increases cost per mag (~$35-$45 each).
No iron sights included — adds minimum $80-$150 to initial cost for a quality backup sight set.
22 ARC ammunition niche — less available and more expensive than .223 Remington, often requiring hand-loading for optimal performance.

Key attributes

upc	810148627041
manufacturer	CMMG
manufacturer part number	28A670CAB
action	Semi-Auto
atf type	MODERN SPORTING RIFLE
barrel length	16.10"
caliber/gauge	.22 ARC
capacity	10 + 1
color	Black
length	39.6500
model	Resolute
safety	Ambidextrous Safety Lever
shipping weight	10.6
sights	No
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 lowers?: Yes, the Resolute MK4 lower receiver is mil-spec dimensionally and will mate with any standard AR-15 upper receiver. However, the bolt carrier group and barrel are chambered specifically for 22 ARC, which uses a bolt face and barrel extension distinct from 5.56 NATO/.223 Remington. You cannot simply drop a 5.56 BCG into this upper and expect it to function or be safe.
Does the 22 ARC work with .223 Remington magazines?: No. The 22 ARC cartridge is based on the 6.5 Grendel case, not the .223 Remington. It requires specific magazines, like the included CMMG 10-rounder or ARC-pattern magazines from Duramag or ASC. Attempting to force-feed 22 ARC rounds into a standard .223/5.56 PMAG will result in malfunctions and potential damage to the feed lips.
How long does shipping take to an FFL?: For in-stock items like this, Ironclad Armory typically processes and ships within 1-2 business days. Transit time via carrier (usually UPS or FedEx) adds 3-7 business days depending on destination. The total timeline from order to your chosen FFL receiving the firearm is typically 5-10 business days, not including the FFL's processing time for your background check.
Can I attach a suppressor to the threaded barrel?: Absolutely. The barrel is threaded 1/2"-28, which is the standard pitch for .22 caliber suppressors. You would direct-thread a compatible suppressor or use a muzzle device like a Dead Air KeyMo or SilencerCo ASR mount if your suppressor uses a QD system. Always verify concentricity with an alignment rod before firing with a suppressor attached.
Does this rifle come with iron sights?: No, it does not. The CMMG Resolute MK4 is sold as an optics-ready platform. The flat-top upper receiver has a Picatinny rail for mounting a scope or red dot, and the M-LOK handguard allows for mounting offset or backup iron sights. You will need to budget for and install your preferred sighting system separately.

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.