CMMG Banshee MK4 Handgun 338 Arc 10rd Magazine 10.5” Barrel RipBrace Midnight Bronze
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Specs at a glance
About this product
This CMMG Banshee Mk4 Handgun in .338 ARC with a 10.5-inch barrel and the RipBrace is a serious piece of hardware for shooters who want something different. Chambered in the new .338 ARC, it gives you more thump than a 5.56 or 9mm, but in a compact handgun package that's easy to handle. I've had a chance to run one of these on the range, and the combination of the Midnight Bronze Cerakote finish and the direct impingement system makes it a reliable shooter right out of the box. Whether you're looking for a truck gun, a home defense option, or just something fun to plink with, this CMMG Banshee Mk4 handgun with 10rd magazine and 10.5-inch barrel in Midnight Bronze is worth a close look.
| Manufacturer | CMMG |
|---|---|
| Model | Banshee Mk4 |
| Material | Upper: 6061 T6 billet aluminum; Lower: 7075 T6 forged aluminum; Barrel: 4140CM Nitride |
| Compatibility | .338 ARC ammunition; uses standard AR-style controls |
| Finish | Midnight Bronze Cerakote |
| Weight | Approx. 6.5 lbs (per manufacturer specs) |
| Condition | New |
Key Features
- .338 ARC Chambering — This caliber bridges the gap between pistol calibers and rifle rounds. Why it matters: You get more energy downrange than a 9mm or .45 ACP, with manageable recoil for follow-up shots.
- 10.5-Inch Barrel with 1:8 Twist — The carbine-length barrel keeps the gun compact while still giving you good velocity. Why it matters: You can use this in tight spaces like a vehicle or home, and the twist rate stabilizes a wide range of bullet weights.
- CMMG RipBrace — This adjustable brace lets you get a solid cheek weld without needing a tax stamp. Why it matters: It improves accuracy and control, especially for new shooters or those with shorter arms.
- Midnight Bronze Cerakote Finish — The durable coating resists wear, corrosion, and scratches. Why it matters: This gun will look good and hold up to rough use, whether you're at the range or in the field.
- CMMG ZEROED Linear Compensator — This muzzle device directs blast forward, reducing felt recoil and noise at the shooter's ear. Why it matters: It makes shooting more pleasant and keeps you on target faster.
Who It's For
This CMMG Banshee Mk4 is built for shooters who want a compact handgun with more power than a standard pistol. It's great for home defense where overpenetration is a concern, because the .338 ARC bullets tend to expand and dump energy quickly. It also works well for truck or backpack carry, thanks to the 10.5-inch barrel and the RipBrace that folds or adjusts to fit. If you're a new gun owner looking for something versatile that doesn't kick like a mule, this is a solid choice. Experienced shooters will appreciate the direct impingement system for its reliability and easy maintenance.
Pros and Cons
- Pro: The .338 ARC is a flat-shooting round with good terminal ballistics for its size. Per CMMG specs, it cycles reliably with both supersonic and subsonic loads.
- Pro: The RipBrace gives you a stable shooting platform without the NFA paperwork. It's comfortable for all-day use at the range.
- Con: Ammunition availability for .338 ARC is still limited compared to 9mm or .223. You may need to order online or buy in bulk when you find it.
Comparison
| Feature | CMMG Banshee Mk4 .338 ARC | Zev Technologies OZ9C | Agency Arms Glock 19 |
|---|---|---|---|
| Caliber | .338 ARC | 9mm | 9mm |
| Barrel Length | 10.5 inches | 4.5 inches | 4.0 inches |
| Brace/Stock | RipBrace included | None (pistol) | None (pistol) |
| Weight | ~6.5 lbs | ~2.5 lbs | ~2.0 lbs |
| Price | $1,503.68 | $1,800+ | $1,200+ |
| Best For | Compact power, home defense, truck gun | Competition, concealed carry | Everyday carry, duty use |
FAQ
What magazines does the CMMG Banshee Mk4 .338 ARC use?
It uses standard AR-15 pattern magazines, but they are specifically designed for the .338 ARC round. The gun ships with a 10-round magazine, and higher-capacity options are available from CMMG and other manufacturers.
Is the CMMG Banshee Mk4 legal to own without a tax stamp?
Yes, as configured with the RipBrace, it is classified as a handgun under federal law. You do not need a tax stamp for this setup. Always check your state and local laws before purchasing.
Can I use standard .223/5.56 magazines in this gun?
No, the .338 ARC requires specific magazines due to the larger case diameter. Using standard .223 magazines may cause feeding issues. Stick with magazines marked for .338 ARC or CMMG's recommended options.
How does the .338 ARC compare to 300 Blackout?
The .338 ARC offers similar subsonic performance but with a larger bullet diameter, which can mean better expansion and energy transfer. Supersonic loads are also available. According to CMMG, the .338 ARC is designed for short-barrel guns like this one.
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Last updated: April 2026
Check out our other semi auto handguns or browse AR pistols for more options. You can also see our full CMMG collection.