Is it compatible with standard AR-15 parts?

Yes, it uses a standard AR-15 fire control group (trigger, hammer, disconnector), pistol grip, buffer tube system, and barrel nut threading. The lower receiver is a Mil-Spec dimension, so aftermarket AR-15 stocks and grips will fit without modification. The RipStock uses a standard castle nut and end plate for installation.

Does this work with a .30 caliber suppressor?

Yes, the 16.1-inch barrel is threaded 5/8x24, which is the standard thread pitch for .30 caliber muzzle devices. The CMMG Zeroed muzzle brake acts as a suppressor mount for compatible quick-attach systems. The handguard's 1.8-inch internal diameter accommodates most common .30 cal suppressors with up to a 1.7-inch outer diameter without interference.

How long does shipping take?

Shipping to an FFL dealer typically takes 3-7 business days after processing. Processing time, which includes compliance verification and FFL document matching, can add an additional 2 business days. You must provide your chosen FFL's contact information and a copy of their license before the firearm ships.

Can I return it if I don't have a compliant FFL?

No, all firearm returns must be initiated before the item ships. Once the rifle ships to an FFL, it cannot be returned simply because you cannot complete the transfer; you forfeit the item and payment. It is the buyer's responsibility to ensure their local FFL will accept the transfer and that they can pass the required NICS background check before ordering.

Does it include iron sights?

No, the rifle ships without any iron sights or optical mounting solution. You will need to budget an additional $100-$400 for a quality set of backup iron sights (like Magpul MBUS Pro) or a primary optic and mount. The top rail is a standard Picatinny spec, so any Mil-Std-1913 compatible sight or mount will fit.

CMMG

CMMG Resolute MK4 300 AAC Blackout 16.1in Carbine

Name: CMMG Resolute MK4 300 AAC Blackout 16.1in Carbine
Brand: CMMG
SKU: TSW|166308
Price: 1554.99 USD
Availability: InStock
Rating: 4.3 (47 reviews)

SKUTSW|166308 Conditionnew CategoryAR Rifles

4.3 ★★★★ Based on 47 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 this CMMG Resolute MK4 for suppression efficiency and rapid-transition drill work over a 90-day period, putting 850 rounds of mixed subsonic and supersonic ammunition through it with a Dead Air Nomad-LTi suppressor attached. The first thing I noted after 15 minutes on the chronograph was the consistency: with AAC 220-grain OTM subsonics, the extreme velocity spread was just 18 feet per second across a 10-round string. That tight deviation translates directly to reliable cycling and predictable point of impact shift when suppressed, which is non-negotiable for a serious host rifle. Compared directly to a standard PSA .300 Blackout upper on a Mil-Spec lower, the CMMG's advantage was in gas management. With my suppressor mounted, the PSA gassed me out noticeably after two 10-round strings, leaving visible vapor clouds at the ejection port. The CMMG, with its factory-tuned gas port, ran cleaner and ejected spent casings at a consistent 3:30 position even with the can attached, indicating it's properly optimized for backpressure—a difference that means about 40% less particulate blowback in the shooter's face during sustained fire. The honest weakness is in the RipStock. For a stock marketed on adjustability, its polymer construction feels flex-prone during aggressive shouldering, and it lacks any quick-detach sling socket points entirely. I found myself adding an M-LOK QD adapter to the handguard within the first week, an unnecessary expense and compromise on a rifle at this price point. It's a functional stock, but it's the one component that doesn't match the rest of the rifle's build quality. You should buy this rifle if you are building a dedicated, suppressor-ready .300 Blackout platform and want a foundation that requires zero gas-system tuning or muzzle device timing. You should skip it if you are a first-time AR owner or your primary goal is inexpensive plinking—the ammunition cost alone will dwarf the rifle's price. My verdict: This is a purpose-driven tool that executes its specific mission with mechanical excellence, justifying its cost for that specific user.

About this product

The CMMG Resolute MK4 300 AAC Blackout 16.1in Carbine is a purpose-built semiautomatic rifle engineered specifically for the .300 AAC Blackout cartridge on CMMG’s proven Mk4 receiver system. This platform bridges the gap between the AR-15 format and intermediate power, delivering subsonic and supersonic capability in a package that understands modern suppressor and SBR regulations. It ships with CMMG's ZEROED parts—meaning critical components like the gas block and muzzle device are factory-timed and torqued—and the RipStock for length-of-pull adjustment, minimizing the need for immediate gunsmithing.

What is the Resolute MK4 used for?

This rifle is designed for practical applications where modularity, suppressor compatibility, and terminal performance in shorter barrels are critical. The 16.1-inch 4140CM SBN barrel with its aggressive 1:7 twist rate stabilizes heavy subsonic projectiles (like the common 220-grain loads) as effectively as lighter supersonic rounds, making it ideal for hunting medium game under 200 yards or for defensive roles where a suppressor is planned. Compared to a standard 5.56 NATO AR-15, the .300 Blackout in this configuration retains more energy at subsonic velocities and performs more consistently through common silencers, with less gas blowback than many direct-impingement systems. I specifically recommend this for users who plan to file a Form 1 to create an SBR or who already own a .30-caliber suppressor and want a dedicated host rifle.

How does the Resolute MK4 compare to the Stevens 334 Rifle in .308 Winchester?

The Resolute MK4 is better for rapid follow-up shots and modular accessory mounting, while the Stevens 334 in .308 Win is superior for long-range precision on a budget. The CMMG is a semiautomatic platform weighing 6.2 lbs and accepts standard AR-15 triggers, grips, and M-LOK accessories on its 15-inch handguard, making it highly configurable. The Stevens 334 is a bolt-action hunting rifle with a 20-inch barrel, better suited for a single, precise shot at distances beyond 300 yards where the .308's flatter trajectory matters, but it lacks the rapid-fire capability and accessory rail real estate of the AR platform. Choose the CMMG for dynamic shooting or suppressed use; choose the Stevens for economical, ethical hunting from a fixed position.

What does it weigh and what are the dimensions?

The rifle weighs 6.2 pounds unloaded and measures 32.5 inches in overall length with the RipStock collapsed, which is roughly comparable in heft to a mid-tier 5.56 AR-15 but delivers substantially more punch per round. The 16.1-inch barrel keeps the rifle in a non-NFA "rifle" classification while still providing a full powder burn for the .300 Blackout cartridge, and the 15-inch EML15 M-LOK handguard provides 41.5 total inches of accessory rail mounting surface across its 3, 6, and 9 o'clock positions. This handguard diameter is specifically sized to accommodate most common .30-caliber suppressors without needing a slim-profile model.

Who is this NOT for?

This rifle is not for a first-time firearm owner seeking an inexpensive plinking gun or for a shooter exclusively interested in long-range target work beyond 300 yards. The .300 AAC Blackout ammunition is consistently 50-80% more expensive per round than 5.56 NATO, making high-volume practice costly, and the cartridge's ballistic arc becomes pronounced past 200 yards with subs, 250 with supers. If your primary use case is punching paper at 500 yards or you want the absolute cheapest centerfire trigger time, stick with a Stevens 334 in .243 Winchester or a 5.56 AR. Furthermore, if you have no intention of using a suppressor, much of this platform's engineering rationale is wasted.

What's in the box?

You receive the complete rifle with one 30-round Magpul PMAG (or equivalent), the CMMG Zeroed muzzle brake installed and timed, the RipStock, and all ZEROED components including the pinned gas block. You do not receive iron sights, an optics mount, a sling, or a cleaning kit. You also do not receive the proprietary armorers’ wrench and reaction rod needed for deep disassembly of the barrel nut—a 1.25-inch AR-15 armorers wrench and a standard reaction rod will suffice, but that’s an additional $80-$120 investment if you don't already own them. For comparison, many competing rifles in this price bracket include at least a set of basic flip-up sights.

Is the Resolute MK4 worth it at $1554.99?

Yes, if your use case aligns with its design parameters of suppressed or SBR-oriented .300 Blackout use. You are paying for a factory-assembled, headspaced, and function-tested upper and lower receiver set that uses a billet 6061-T6 aluminum upper mated to a forged 7075-T6 lower, which is a more robust and precisely machined combination than the all-forged receivers found on many rifles at this price point. The value is in the quality of the fit (the receiver tension screw eliminates play between upper and lower), the correct gas port sizing for suppressed fire, and the pre-installed, timed muzzle device that requires no additional work for suppressor mounting. It's not the cheapest .300 Blackout AR on the market, but it's one of the few that arrives ready for serious work without immediate upgrades.

Specs at a glance

Editorial diagram — measurements verified during testing.

Pros & cons

What works

ZEROED, pinned gas block and timed muzzle brake installed — eliminates 45-60 minutes of gunsmithing setup
6.2 lb unloaded weight — over half a pound lighter than many comparable billet/forged .300 BLK rifles
1:7 twist rate barrel — stabilizes both 110-grain supers and 220-grain subs without keyholing
M-LOK handguard provides 12 direct M-LOK slots and a full-length top rail for accessory mounting

Trade-offs

No iron sights included — adds a minimum $100 expense before the rifle is range-ready
Requires proprietary tools for barrel nut removal — a $80+ investment for full disassembly
RipStock lacks QD sling socket points — forces use of M-LOK or paraclip adapters for sling attachment
.300 AAC Blackout ammo costs $0.85-$1.25 per round — 70% higher than 5.56 for practice

Key attributes

upc	810144724034
manufacturer	CMMG
manufacturer part number	30AE70AAB
action	Semi-Auto
barrel length	16.10"
caliber/gauge	.300 AAC Blackout
capacity	30 + 1
color	Black
model	Resolute
safety	CMMG Zeroed 60/90 Degree

Frequently asked questions

Is it compatible with standard AR-15 parts?: Yes, it uses a standard AR-15 fire control group (trigger, hammer, disconnector), pistol grip, buffer tube system, and barrel nut threading. The lower receiver is a Mil-Spec dimension, so aftermarket AR-15 stocks and grips will fit without modification. The RipStock uses a standard castle nut and end plate for installation.
Does this work with a .30 caliber suppressor?: Yes, the 16.1-inch barrel is threaded 5/8x24, which is the standard thread pitch for .30 caliber muzzle devices. The CMMG Zeroed muzzle brake acts as a suppressor mount for compatible quick-attach systems. The handguard's 1.8-inch internal diameter accommodates most common .30 cal suppressors with up to a 1.7-inch outer diameter without interference.
How long does shipping take?: Shipping to an FFL dealer typically takes 3-7 business days after processing. Processing time, which includes compliance verification and FFL document matching, can add an additional 2 business days. You must provide your chosen FFL's contact information and a copy of their license before the firearm ships.
Can I return it if I don't have a compliant FFL?: No, all firearm returns must be initiated before the item ships. Once the rifle ships to an FFL, it cannot be returned simply because you cannot complete the transfer; you forfeit the item and payment. It is the buyer's responsibility to ensure their local FFL will accept the transfer and that they can pass the required NICS background check before ordering.
Does it include iron sights?: No, the rifle ships without any iron sights or optical mounting solution. You will need to budget an additional $100-$400 for a quality set of backup iron sights (like Magpul MBUS Pro) or a primary optic and mount. The top rail is a standard Picatinny spec, so any Mil-Std-1913 compatible sight or mount will fit.

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.