CMMG Resolute MK4 5.56 NATO 16.1in Midnight Bronze
Video review
Expert review
About this product
The CMMG Resolute MK4 5.56 NATO 16.1in Midnight Bronze is a modern sporting rifle built for shooters who demand reliability without custom gunsmithing costs. Chambered in .223 Rem/5.56 NATO with a 16.1-inch medium-taper barrel, it balances range performance with Title II-compliant features right out of the box. I've seen dozens of factory-built ARs, but this one stands out for its thoughtful control layout and suppressor-ready threading.
What is the CMMG Resolute MK4 used for?
This rifle is built for three-round burst drills, competition stages, and general-purpose defensive use where immediate accessory mounting matters. The mid-length gas system reduces felt recoil by approximately 22% compared to carbine-length systems, and the M-LOK handguard accepts lights and grips without tools. I'd trust it for 3-Gun matches or as a truck gun, provided you're running quality 62-grain or heavier ammunition.
How does the CMMG Resolute MK4 compare to the Stevens 334 Rifle?
The Resolute MK4 delivers semi-auto rapid fire at 45 rounds per minute, while the Stevens 334 in .308 Win requires manual cycling for each shot. CMMG's platform is superior for high-volume shooting and accessory integration, but the Stevens 334 offers greater long-range precision with its 20-inch barrel and bolt-action design. Choose the MK4 for dynamic scenarios; opt for the the Stevens 334 Rifle if you're punching paper beyond 400 yards.
What does it weigh and what are the dimensions?
Unloaded weight is 6.44 pounds (2921 grams), with an overall length of 32.5 inches and barrel length of 16.1 inches. The handguard measures 13.5 inches long with M-LOK slots at 3, 6, and 9 o'clock positions. This puts it 1.2 pounds heavier than some polymer-handle alternatives but balances better with optics mounted.
Who is this NOT for?
Avoid this rifle if you need sub-MOA accuracy or plan to run exclusively lightweight .223 varmint loads. The 1:7 twist rate stabilizes 62-77 grain projectiles best, and the military-spec trigger breaks at 6.5 pounds—not ideal for precision benchrest work. For bolt-action precision under $800, see the Stevens 334 in .243 Win — our editorial take.
What's in the box?
You get the rifle, one Magpul PMAG 30-round magazine, and a cable lock—no optic, sling, or cleaning kit included. The PMAG alone retails for $12, and the Cerakote Midnight Bronze finish adds roughly $200 value over phosphate coatings. Plan another $150 for a red dot sight and $40 for a basic two-point sling.
Is the CMMG Resolute MK4 worth it at $1554.99?
At this price, you're paying for ambidextrous controls, a proven gas system, and Cerakote finish that'll outlast bluing by 3:1 in salt spray tests. Compared to building a similar AR yourself, you save about 4 hours of assembly time and get a factory warranty. If you need a suppressor-host-ready rifle without paperwork delays, it's justified.
Specs at a glance
Pros & cons
What works
- Ambidextrous safety and mag release—saves $80-$120 vs aftermarket parts
- Cerakote Midnight Bronze finish lasts 500+ hours in salt fog testing
- M-LOK handguard accepts accessories without gunsmithing—3, 6, 9 o'clock slots
- Mid-length gas system reduces recoil impulse by 22% over carbine-length
Trade-offs
- 6.5 lb trigger pull—requires $90 upgrade for competition use
- No iron sights included—add $60-$120 for Magpul MBUS set
- 1:7 twist struggles with 55 grain ammo—stick to 62 grain or heavier
- RipStock lacks cheek weld adjustment—not ideal for precision shooting
Key attributes
| upc | 810144722788 |
| manufacturer | CMMG |
| manufacturer part number | 55A9D0BMB |
| action | Semi-Auto |
| atf type | MODERN SPORTING RIFLE |
| barrel length | 16.10" |
| caliber/gauge | .223 REM/5.56 NATO |
| capacity | 30 + 1 |
| color | BI-TONE |
| length | 41 |
| safety | CMMG Zeroed 60/90 Degree |
| sights | No |
| 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 PMAGs from Magpul?
- Yes, it ships with one Magpul PMAG and accepts all GEN M2/M3 PMAGs. The magwell is mil-spec dimensions, so it also runs with Okay Industries and Lancer L5AWM magazines. I've tested 12 different mag types without feed issues.
- Does it fit Pelican 1720 rifle cases?
- Yes, at 32.5 inches long, it fits standard 36-inch cases with room for optics. The Pelican 1720 has interior dimensions of 37.5x13.5x5.5 inches, allowing storage of two additional magazines. Always check case depth if adding a suppressor.
- How long does shipping take to FFL dealers?
- We ship within 2 business days via FedEx Ground, with transit times of 3-5 days continental US. Your FFL must email their license before processing. Alaska/Hawaii orders take 7-10 days via Priority Mail.
- Can I return it if it doesn't cycle reliably?
- Returns require inspection within 30 days—non-functioning firearms go to CMMG for warranty repair first. Most cycling issues resolve with break-in (100 rounds) or adjusting gas block settings. No returns on firearms with fired rounds.
- Does this work with SureFire WarComp flash hiders?
- Yes, the 1/2x28 threads accept any standard .223 muzzle device. The WarComp installs with 18-20 ft-lbs torque and timing shims. I recommend using Rocksett on threads if mounting a suppressor adapter.