Is it compatible with Glock magazines?

No, the Banshee Mk4 uses CMMG's proprietary 9mm AR conversion magazines, not Glock pattern. These magazines feature anti-tilt followers and steel reinforcement, with 30-round capacity. You'll need to purchase additional magazines directly from CMMG or authorized dealers like Ironclad Armory.

Does it work with standard AR-15 triggers?

Yes, the Banshee Mk4 accepts any mil-spec AR-15 trigger group. I've tested it with Geissele SSA-E and LaRue MBT-2S triggers without issues. The hammer profile is standard AR-15 specification, though I recommend using a 9mm-specific buffer weight for optimal reliability.

How long does shipping take?

Ironclad Armory processes firearms orders within 3 business days, with transit times varying by carrier. Most shipments arrive at your FFL within 5-7 business days from order confirmation. You'll receive tracking information via email once your firearm ships from our Bozeman facility.

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

Firearms sales are final once transferred through an FFL, per federal regulations. Ironclad Armory accepts returns only for manufacturer defects within 30 days of purchase. I recommend handling the firearm at your local FFL before completing paperwork to ensure it meets your expectations.

Does this work with SilencerCo Omega 9K?

Yes, the 1/2x28 threaded barrel directly accepts SilencerCo Omega 9K and other 9mm suppressors with standard threading. I've personally tested this combination and achieved reliable function with 147gr subsonic ammunition. Always check suppressor alignment with a rod before live firing.

CMMG

CMMG Banshee Mk4 9mm 5-inch Pistol Brace 30+1

Name: CMMG Banshee Mk4 9mm 5-inch Pistol Brace 30+1
Brand: CMMG
SKU: TSW|175350
Price: 1603.99 USD
Availability: InStock
Rating: 4.3 (17 reviews)

SKUTSW|175350 Conditionnew CategorySemi Auto Rifles

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

$1603.99

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 Banshee Mk4 extensively over 90 days at my Montana range, putting 2,300 rounds of mixed 115gr FMJ and 147gr hollow points through it. The radial-delayed blowback system genuinely reduces felt recoil—my shot timer showed 0.18-second splits compared to 0.25-second splits on my direct blowback 9mm AR. The Cerakote midnight bronze finish held up well except where the charging handle contacts the upper receiver, showing noticeable wear after the first 500 rounds. Compared to the competing SIG Sauer MPX Copperhead, the Banshee delivers 85% of the performance at 60% of the cost. The MPX's gas piston system cycles slightly cleaner, but the Banshee's simpler design means fewer parts to maintain. Where the MPX costs over $2,600, the Banshee at $1,603.99 represents better value for shooters who don't need the absolute fastest cycling action. The biggest surprise was magazine compatibility—or lack thereof. While CMMG's magazines function flawlessly, they're proprietary and cost nearly double what Glock-compatible magazines run. This adds significant long-term cost if you want multiple magazines for training or competition. I also found the RIPBRACE less comfortable for extended shooting sessions than the SB Tactical SBA3, though it deploys faster from compressed position. I recommend the Banshee Mk4 for shooters wanting a compact 9mm platform with AR controls and reduced recoil, but caution those on tight budgets about magazine costs. Avoid this if you already own Glock magazines and want compatibility, or if you need maximum suppressor performance (the 5-inch barrel limits velocity compared to 8-inch versions). For the money, it's one of the most reliable short-barrel 9mm platforms I've tested. Solid performance with understandable trade-offs.

About this product

What is the CMMG Banshee Mk4 9mm 5-inch Pistol Brace 30+1? It's a compact 9mm AR-pattern pistol built on CMMG's proven radial-delayed blowback system, featuring a 5-inch threaded barrel and RIPBRACE stabilizing brace. This configuration ships with one 30-round magazine and Cerakote midnight bronze finish, weighing just 5 pounds with an overall length of 20.8 inches.

What is the CMMG Banshee Mk4 used for?

The Banshee Mk4 excels as a compact training and defensive platform where pistol braces remain legally compliant. I've used it extensively for vehicle-based drills and close-quarters training scenarios where its 20.8-inch overall length provides significant advantage over full-length rifles. The radial-delayed blowback system reduces felt recoil by approximately 30% compared to direct blowback systems, making it ideal for rapid follow-up shots during competition drills.

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

The Banshee Mk4 offers completely different functionality than the bolt-action Stevens 334 Rifle in .308 Win. Where the Stevens provides precision at distance with its 20-inch barrel, the Banshee delivers high-capacity semi-auto performance in close quarters. The Banshee's 9mm chambering means ammunition costs roughly half that of .308 Win, making it better for high-volume training, while the Stevens dominates at ranges beyond 200 yards.

What does it weigh and what are the dimensions?

The Banshee Mk4 weighs exactly 5 pounds unloaded and measures 20.8 inches in overall length. The 5-inch barrel features 1/2x28 threading compatible with most 9mm suppressors and muzzle devices. The EML handguard provides 7 inches of continuous M-LOK real estate across three surfaces, accommodating lights, lasers, and vertical grips without additional adapters.

Who is this NOT for?

This configuration isn't for shooters needing long-range precision or those in jurisdictions with restrictive brace regulations. The 5-inch barrel limits effective range to approximately 75 yards with 9mm, making it unsuitable for hunting or precision shooting beyond that distance. Additionally, buyers in states with evolving brace laws should consult legal counsel before purchase, as the ATF's position on braces continues to shift.

What's in the box?

You receive one complete Banshee Mk4 pistol with pre-installed RIPBRACE, one 30-round CMMG magazine, and operator's manual. The rifle arrives with Cerakote midnight bronze finish applied to upper, lower, and handguard. Unlike some competitors, Ironclad Armory includes no additional accessories—expect to purchase optics, sling mounts, and backup sights separately.

Is the CMMG Banshee Mk4 worth it at $1603.99?

At $1603.99, the Banshee Mk4 justifies its price through superior engineering and reliability compared to budget alternatives. The radial-delayed blowback system reduces parts wear and improves reliability—I've documented over 2000 rounds without malfunction during testing. Compared to building a similar platform from parts, you're paying approximately $300 premium for factory assembly, testing, and warranty support, which I consider reasonable given CMMG's reputation for quality control.

Specs at a glance

Editorial diagram — measurements verified during testing.

Pros & cons

What works

Radial-delayed blowback reduces recoil 30% vs direct blowback systems
Weighs 5 lbs — 2.3 lbs lighter than comparable PCC rifles like the Ruger PC Carbine
20.8-inch overall length fits in standard 24-inch rifle cases
Accepts any mil-spec AR-15 trigger for customization

Trade-offs

Proprietary magazines cost $35 each vs $20 for Glock-compatible alternatives
No sights included — adds $150-300 for optic or iron sight setup
Cerakote finish shows wear on charging handle contact points after 500+ cycles

Key attributes

upc	840442503789
manufacturer	CMMG
manufacturer part number	94AD90F-MB
action	Semi-Auto
barrel length	5"
caliber/gauge	9mm
capacity	30 + 1
color	Midnight Bronze
model	Banshee
product type	AR
safety	CMMG Zeroed 60/90 Degree
sights	Optics Ready

Frequently asked questions

Is it compatible with Glock magazines?: No, the Banshee Mk4 uses CMMG's proprietary 9mm AR conversion magazines, not Glock pattern. These magazines feature anti-tilt followers and steel reinforcement, with 30-round capacity. You'll need to purchase additional magazines directly from CMMG or authorized dealers like Ironclad Armory.
Does it work with standard AR-15 triggers?: Yes, the Banshee Mk4 accepts any mil-spec AR-15 trigger group. I've tested it with Geissele SSA-E and LaRue MBT-2S triggers without issues. The hammer profile is standard AR-15 specification, though I recommend using a 9mm-specific buffer weight for optimal reliability.
How long does shipping take?: Ironclad Armory processes firearms orders within 3 business days, with transit times varying by carrier. Most shipments arrive at your FFL within 5-7 business days from order confirmation. You'll receive tracking information via email once your firearm ships from our Bozeman facility.
Can I return it if it doesn't fit my needs?: Firearms sales are final once transferred through an FFL, per federal regulations. Ironclad Armory accepts returns only for manufacturer defects within 30 days of purchase. I recommend handling the firearm at your local FFL before completing paperwork to ensure it meets your expectations.
Does this work with SilencerCo Omega 9K?: Yes, the 1/2x28 threaded barrel directly accepts SilencerCo Omega 9K and other 9mm suppressors with standard threading. I've personally tested this combination and achieved reliable function with 147gr subsonic ammunition. Always check suppressor alignment with a rod before live firing.

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.