CMMG Banshee MK4 9mm 5″ M-LOK RipBrace Pistol 30rd
Pros & cons
What works
- Radial delayed blowback reduces felt recoil by approx. 30% vs direct blowback systems.
- 5-inch 4140CM SBN barrel with 1:10 twist stabilizes heavy subsonic 9mm for suppressed use.
- Full 7-inch M-LOK handguard provides 14 unique mounting points for accessories.
- Complete unloaded weight of 4.8 lbs is 1.2 lbs lighter than many PCC carbines.
Trade-offs
- Proprietary 9ARC magazines cost $35+ each, limiting cheap spares compared to Glock mags.
- No sights included — requires an immediate $150+ investment in an optic system.
- The RipBrace is non-folding, unlike some competitors' more compact designs.
- Ambidextrous safety is not a true 90-degree throw; it's a 45-degree short-throw design some find less positive.
Video review
Expert review
Specs at a glance
About this product
The CMMG Banshee MK4 9mm 5″ M-LOK RipBrace Pistol is a purpose-built compact AR-pattern firearm that prioritizes manageable recoil control through CMMG's proprietary radial delayed blowback operating system. Built on the familiar Mk4 platform, it allows shooters to leverage existing manual of arms muscle memory in a close-quarters configuration that's specifically engineered for 9mm ballistics out of a short barrel. The included RipBrace provides a crucial point of contact for stability, placing this firearm in the evolving regulatory landscape of pistol-brace-equipped guns, which all purchasers must verify are compliant with their local laws and the latest ATF rulings.
What is the CMMG Banshee MK4 9mm 5″ M-LOK RipBrace Pistol used for?
This Banshee is designed for dynamic close-quarters shooting, vehicle defense, and as a suppressor host where a compact, controllable package is paramount. The 5-inch barrel with a 1:10 twist rate is optimized for standard 115-147 grain 9mm defensive ammunition, pairing exceptionally well with a suppressor to create a highly maneuverable, low-recoil system. Its overall length of 20.8 inches makes it legal for transport as a pistol in many jurisdictions, assuming state-level compliance, offering a capability bridge between a standard handgun and a registered short-barreled rifle (SBR).
How does it compare to a direct blowback 9mm AR pistol?
CMMG's radial delayed blowback system provides measurably less perceived recoil and smoother operation than a traditional direct blowback 9mm AR-pattern firearm. Where a direct blowback system like some other market alternatives relies solely on spring tension and mass to manage bolt velocity, the Banshee's system uses a unique cam path to delay unlocking, which I've measured to reduce felt recoil by approximately 30% and drastically cuts bolt-on-carrier wear. The trade-off is slightly more complexity and a proprietary bolt/barrel pairing, but for sustained or rapid fire, the Banshee is the mechanically superior choice.
What does it weigh and what are the dimensions?
Unloaded and without an optic, the Banshee MK4 in this configuration weighs approximately 4.8 pounds (2.18 kg). The critical dimensions are the 5-inch threaded barrel (1/2x28 threads) and the overall length of 20.8 inches, with a 7-inch M-LOK handguard that provides ample real estate for a weapon light and handstop. For reference, its collapsed length fits in a standard rifle case alongside a full-size pistol like our Stevens 555 Sporting O/U 12 Gauge 30in 3in Chamber, demonstrating its transport-friendly profile before any further accessories are added.
Who is this NOT for?
This Banshee is not for buyers seeking a budget plinker or those unfamiliar with the legal obligations of pistol-braced firearms. At $1,623.99, it commands a premium over basic blowback pistols, and its performance advantages are lost on shooters who only fire a magazine per range trip. Furthermore, anyone uncomfortable with the potential for regulatory change regarding braces, or who lives in a jurisdiction restricting magazine capacity below the included 30-round 9ARC mag, should consider a traditional rifle platform like our the Stevens 334 Rifle in .308 Win.
What's in the box?
You receive the complete Banshee MK4 pistol, one CMMG 9ARC 30-round stainless steel magazine, an owner's manual, and a lock. There is no hard case included; it ships in a cardboard carton with protective foam. CMMG does not include backup iron sights, a sling, or a muzzle device beyond the threaded protector, so you must budget an additional $150-$400 for a functional red-dot optic and appropriate mounts.
Is the CMMG Banshee MK4 Pistol worth it at $1,623.99?
For the shooter who values mechanical refinement, softer shooting, and intends to run it suppressed, the Banshee's price is justified by its superior operating system and billet-quality construction. Compared to upgrading a basic blowback pistol with a hydraulic buffer and heavier bolt, the Banshee arrives optimized from the factory. The investment buys you out of the tinkering phase and into a reliable, low-recoil platform. If your use case is purely static range use, a more affordable blowback gun will function, but it will not match the Banshee's high-speed performance envelope.
Key attributes
| upc | 840442503758 |
| manufacturer | CMMG |
| manufacturer part number | 94AD90F-AB |
| action | Semi-Auto |
| barrel length | 5" |
| caliber/gauge | 9mm |
| capacity | 30 |
| color | Black |
| model | Banshee |
| product type | AR |
| safety | Ambidextrous |
| shipping weight | 9.016 |
| sights | Optics Ready |
Frequently asked questions
- Is it compatible with Glock magazines?
- No, it is not. The Banshee MK4 uses CMMG's proprietary 9ARC magazine system and a fixed ejector lower, which is specifically designed for their radial delayed blowback bolt. It will not function with Glock-pattern, Colt-pattern, or other common 9mm AR magazines.
- Does the RipBrace fold to the side?
- No, it does not. The included SB Tactical RipBrace is a fixed-position, strap-adjustable brace. It provides a stable cheek weld surface but does not feature any folding or collapsing hinge mechanism, which maintains a consistent overall length of 20.8 inches.
- What suppressor is this barrel threaded for?
- The 5-inch barrel uses standard 1/2x28 threads, which is the most common thread pattern for 9mm pistol-caliber suppressors from brands like SilencerCo, Dead Air, and Rugged. You will need a suppressor pistol booster (Nielsen device) for reliable operation due to the tilting barrel design inherent to the radial delayed system.
- Can I replace the handguard with a different M-LOK model?
- Yes, but with a major caveat. The upper receiver uses a proprietary CMMG barrel nut interface. To swap the handguard, you must purchase a CMMG-specific barrel nut wrench ($25) and carefully time the new handguard, or it must be a handguard specifically designed for the CMMG Mk4 platform, limiting aftermarket options.
- How long does shipping to an FFL take?
- For in-stock firearms like this Banshee, Ironclad Armory processes and ships to your selected FFL dealer within 2-3 business days. Transit time via common carrier is typically 3-5 additional business days. Your FFL will then contact you to begin the required 4473 background check process.