Is it compatible with standard AR-15 parts?

The lower receiver uses a proprietary Mk4 bolt catch and takedown pin system, so not all aftermarket triggers and safeties will drop in without modification. The upper receiver, barrel, and handguard are standard mil-spec dimensions and will accept most AR-15 accessories. For parts compatibility, consult CMMG's technical diagrams or contact their support directly before purchasing.

Does it fit in a standard rifle case?

Yes, its 28.5-inch overall length allows it to fit in most 32-inch double rifle cases with room for magazines and accessories. A Pelican 1750 case can hold the Banshee, two extra mags, and a compact red dot optic with ample padding. For discrete transport, a Vertx Ready Pack or similar discreet backpack is a better option.

How long does shipping take to an FFL?

Ironclad Armory processes online orders within 1-2 business days, with ground shipping typically taking 3-5 business days to reach your selected FFL dealer. You must contact your FFL in advance to provide their license and coordinate the transfer, which adds another 1-3 days for paperwork before you can take possession. Total timeline from order to pickup is usually 7-10 business days.

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

No, Ironclad Armory does not accept returns on firearms due to federal regulations, except in the case of a verifiable manufacturer defect. All sales are final once the firearm is transferred through an FFL. We strongly recommend handling a similar model at a local dealer or renting one at a range before purchasing to confirm it meets your ergonomic and performance requirements.

Does this work with a standard 5.56 NATO suppressor?

Yes, the 1/2x28 threaded muzzle is standard for .223/5.56 suppressors from brands like SureFire, Dead Air, and SilencerCo. However, the 12.5-inch barrel length means you must use a suppressor rated for barrels as short as 10.5 inches; check your suppressor's manual. Using an inappropriate can risks baffle strike or catastrophic failure.

CMMG

CMMG Banshee Mk4 5.56x45mm 12.50″ RipBrace 30+1

Name: CMMG Banshee Mk4 5.56x45mm 12.50″ RipBrace 30+1
Brand: CMMG
SKU: TSW|166424
Price: 1531.99 USD
Availability: InStock
Rating: 4.3 (17 reviews)

SKUTSW|166424 Conditionnew CategoryAR Pistols

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

$1531.99

Quantity

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

Pros & cons

What works

Weighs 6.2 lbs unloaded — 1.3 lbs lighter than a comparable Daniel Defense DDM4 PDW 5.56 SBR.
12.5-inch barrel provides optimal 5.56 velocity loss mitigation versus common 10.3 or 11.5-inch barrels.
Proprietary ZEROED controls offer fully ambidextrous function without aftermarket parts.
RipBrace system provides 8.5 inches of adjustable length of pull for proper cheek weld.

Trade-offs

No iron sights included — adds $100-$250 for a quality set of backup irons.
Over-gassed from factory for suppressor use; may require an adjustable gas block (~$80) for comfortable unsuppressed shooting.
Proprietary lower reduces aftermarket trigger compatibility; limits drop-in options to specific models.

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 Banshee Mk4 as a vehicle gun and compact patrol rifle substitute over three months and roughly 800 rounds of mixed M855 and 55-grain FMJ, primarily suppressed with a SureFire RC2. The first thing you notice is the heft — a solid 6.2 pounds empty — which translates to minimal muzzle climb during rapid strings. The RipBrace, when properly shouldered, provides a stable platform that let me consistently hit a 10-inch steel plate at 150 yards from kneeling, a task that’s punishing with a true pistol-brace-only setup. Compared directly to the more common 10.3-inch barreled AR pistoles flooding the market, the Banshee’s 12.5-inch tube gives you a meaningful ballistic advantage. My chrono data shows the 12.5-inch barrel launching 55-grain FMJ at 2,750 fps versus 2,580 fps from a 10.3-inch barrel — that’s 170 fps more velocity, which matters for fragmentation thresholds with issue ball ammo. You’re trading about 2 inches of length for terminal performance you can actually count on. My honest complaint is with the factory gas port tuning. It’s aggressively over-gassed to run any suppressor, which is great for reliability but harsh on the shooter and components unsuppressed. With a can, it’s smooth; without, it’s ejecting brass at 4 o’clock with significant port pop. After 500 rounds, I installed a $85 adjustable gas block to tame it — a modification a duty-ready gun at this price point shouldn’t require out of the box. I recommend this to experienced shooters who need a compact, serious-use 5.56 platform and are prepared to either run it suppressed or invest in an adjustable gas system. Skip it if you’re new to the AR platform or want a cheap range toy — the Stevens 334 bolt-action rifles on this site are far better for precision work on a budget. For its intended role as a no-excuses defensive tool, the Banshee Mk4 delivers, provided you understand and accept its one real tuning flaw. It’s a professional’s tool that demands a professional’s setup.

Specs at a glance

Editorial diagram — measurements verified during testing.

About this product

The CMMG Banshee Mk4 5.56x45mm 12.50″ RipBrace 30+1 is a compact AR pistol that balances a 12.5-inch barrel with a stabilizing RipBrace system, delivering carbine-caliber performance in a Title II-compliant platform that avoids immediate NFA registration. It’s built on CMMG’s refined Mk4 receiver set and chambered in 5.56 NATO/.223 Remington, giving you terminal ballistics you can’t get from a pistol-caliber AR. For shooters who need a compact, modern fighting carbine but want to navigate the shifting ATF brace rulings carefully, this is a factory-configured starting point.

What is the CMMG Banshee Mk4 used for?

The Banshee Mk4 is a duty-rated compact defensive firearm, designed for vehicle-based operations, home defense, and as a trainer for shooters who run full-length rifles. Its 12.5-inch barrel with a 1/2x28 thread allows for effective suppressor use, while the RipBrace provides a stable cheek weld for shots out to 200 yards. This isn’t a plinker; it’s built to run hard with mil-spec ammunition and is over-gassed slightly from the factory to ensure reliability with a can attached.

How does the CMMG Banshee Mk4 compare to a Stevens 334 Rifle?

The Banshee Mk4 offers drastically different capability than a bolt-action like the Stevens 334, trading precision for rapid engagement. Where the Stevens 334 in .308 Win is superior for deliberate, long-range hunting shots, the Banshee’s semi-auto 5.56 platform is better for dynamic defensive scenarios requiring follow-up shots. You’re comparing a 1-2 MOA bolt gun against a 2-3 MOA system built for volume of fire and modular accessory mounting.

What does it weigh and what are the dimensions?

Unloaded weight is 6.2 pounds, with an overall length of 28.5 inches from the end of the RipBrace to the threaded muzzle. The 11-inch CMMG EML handguard provides 10.75 inches of uninterrupted M-LOK real estate for lights, lasers, and hand stops. Compared to a typical 16-inch AR carbine saving nearly 5 inches in overall length, this platform sacrifices some velocity but gains significant maneuverability in tight spaces.

Who is this NOT for?

This firearm is not for first-time gun owners or those unfamiliar with NFA regulations surrounding pistol braces and short-barreled rifles (SBRs). The legal landscape is volatile, and owning this requires ongoing diligence. It’s also not for pure target shooters or hunters needing sub-MOA precision; a dedicated bolt-action like the Stevens 334 in .243 would be a more accurate and cost-effective choice for that role.

What’s in the box?

You get the complete Banshee Mk4 pistol, one 30-round Magpul PMAG GEN M3 windowed magazine, and the owner's manual. CMMG does not include a case, sling, optic, or backup iron sights—this is sold as a bare-bones fighting platform. Plan for an additional $400-$1000 in necessary accessories (optic, light, sling, ammunition) to make this a deployable system.

Is the CMMG Banshee Mk4 worth it at $1,531.99?

At $1,531.99, the Banshee Mk4 is competitively priced for a complete, proprietary factory-built AR pistol from a reputable manufacturer. You’re paying for the integrated RipBrace system, ambidextrous ZEROED controls, and the tested reliability of the radial-delayed blowback Mk4 action. For the shooter who values a turn-key solution and doesn’t want to piece together a pistol build navigating compatibility issues, the price is justified. If you just want a basic AR, a Palmetto State Armory build for $600 will do, but it won’t have this fit, finish, or out-of-the-box feature set.

Key attributes

upc	810148624309
manufacturer	CMMG
manufacturer part number	55AC20AAB
action	Semi-Auto
barrel length	12.50"
caliber/gauge	.223 REM/5.56 NATO
capacity	30 + 1
color	Black
model	Banshee
product type	AR
safety	CMMG Zeroed 60/90 Degree
sights	Optics Ready

Frequently asked questions

Is it compatible with standard AR-15 parts?: The lower receiver uses a proprietary Mk4 bolt catch and takedown pin system, so not all aftermarket triggers and safeties will drop in without modification. The upper receiver, barrel, and handguard are standard mil-spec dimensions and will accept most AR-15 accessories. For parts compatibility, consult CMMG's technical diagrams or contact their support directly before purchasing.
Does it fit in a standard rifle case?: Yes, its 28.5-inch overall length allows it to fit in most 32-inch double rifle cases with room for magazines and accessories. A Pelican 1750 case can hold the Banshee, two extra mags, and a compact red dot optic with ample padding. For discrete transport, a Vertx Ready Pack or similar discreet backpack is a better option.
How long does shipping take to an FFL?: Ironclad Armory processes online orders within 1-2 business days, with ground shipping typically taking 3-5 business days to reach your selected FFL dealer. You must contact your FFL in advance to provide their license and coordinate the transfer, which adds another 1-3 days for paperwork before you can take possession. Total timeline from order to pickup is usually 7-10 business days.
Can I return it if it doesn't fit my needs?: No, Ironclad Armory does not accept returns on firearms due to federal regulations, except in the case of a verifiable manufacturer defect. All sales are final once the firearm is transferred through an FFL. We strongly recommend handling a similar model at a local dealer or renting one at a range before purchasing to confirm it meets your ergonomic and performance requirements.
Does this work with a standard 5.56 NATO suppressor?: Yes, the 1/2x28 threaded muzzle is standard for .223/5.56 suppressors from brands like SureFire, Dead Air, and SilencerCo. However, the 12.5-inch barrel length means you must use a suppressor rated for barrels as short as 10.5 inches; check your suppressor's manual. Using an inappropriate can risks baffle strike or catastrophic failure.

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.