CMMG Banshee MK4 .300 AAC Blackout 12.5in Pistol – Black

About this product

What is the CMMG Banshee MK4 .300 AAC Blackout 12.5in Pistol? It's a factory-built, short-barrel AR-platform pistol engineered from the ground up for suppressed use and Title I compliance without an NFA stamp, leveraging the ballistic efficiency of the .300 Blackout cartridge in a package that retains full AR-pattern modularity. This isn't a cut-down rifle; CMMG's Mk4 receiver set, proprietary radial-delayed blowback system, and zeroed-out-of-the-box components are designed to function as an integrated system at this specific 12.5-inch barrel length. It arrives configured with a stabilizing brace, putting it in the legal definition of a pistol, which is a critical distinction from an SBR like the popular Daniel Defense DDM4 PDW.

What is the CMMG Banshee MK4 12.5in used for?

The Banshee MK4 is a purpose-built tool for suppressed, close-quarters tactical applications and home defense. Its primary utility is delivering near-rifle terminal ballistics from a sub-16-inch barrel when suppressed, making it exceptionally quiet with subsonic ammunition. The 12.5-inch barrel length is the practical sweet spot for the .300 Blackout round, allowing it to stabilize heavy subsonic projectiles and achieve full powder burn for supersonic loads, all while remaining compact enough for vehicle or structure use. This configuration excels as a dedicated suppressor host with a 5/8x24 threaded muzzle, where its engineered gas system manages backpressure far better than a direct-impingement AR-15 would at this length.

How does the CMMG Banshee MK4 compare to the PSA JAKL 300 BLK Pistol?

The CMMG Banshee MK4 is mechanically superior for suppressor use and recoil management, but costs roughly $500 more than a comparable Palmetto State Armory JAKL. The key difference is CMMG's radial-delayed blowback operating system, which reduces felt recoil by approximately 30% and virtually eliminates gas-to-the-face compared to the JAKL's standard short-stroke piston, a critical advantage when running a can. While the PSA JAKL offers compelling value and shares M-LOK compatibility, the Banshee's ZEROED trigger (a crisp 4.5-lb pull from the factory) and integrated upper/lower fitment demonstrate a higher level of out-of-the-box refinement and purpose-driven engineering. For a budget-conscious range toy, the JAKL is fine; for a duty-reliable suppressed weapon, the Banshee's system justifies the premium.

What does it weigh and what are the dimensions?

Unloaded and without an optic or suppressor, the Banshee MK4 weighs 5.8 pounds (92.8 ounces). Its overall length from the rear of the RipBrace to the muzzle threads is 27.5 inches, with a handguard length of 10.5 inches providing ample real estate for a white light, pressure pad, and handstop. Collapsed, the RipBrace reduces the overall length to approximately 24 inches, making it stowable in a standard tactical backpack. This weight and balance point make it feel more like an overbuilt tactical rifle than a pistol, which is exactly the point—it handles like a premium SBR without the NFA paperwork.

Who is this NOT for?

This pistol is not for a new shooter looking for a cheap plinker or someone unwilling to invest in a suppressor and specialized ammunition. The .300 AAC Blackout round costs nearly twice as much per round as 5.56 NATO, negating its ballistic advantages if you're just punching paper at 50 yards. It's also a poor choice for someone wanting a traditional hunting rifle; its effective range is capped at around 200 yards, and its pistol configuration makes it legally complex to shoulder in some jurisdictions—for that, a dedicated bolt-action hunting platform is far more appropriate. Finally, if your sole concern is absolute minimum size, a true 5.5-inch barrel 300 BLK pistol will be more compact, though at a significant ballistic cost.

What's in the box?

You receive one complete CMMG Banshee MK4 pistol, one 30-round Magpul PMAG GEN M3 magazine, the installed CMMG ZEROED Linear muzzle device, a Picatinny rail section for M-LOK attachment, and all necessary paperwork. Notably absent is any form of optic, sling, or white light, which are considered mission-critical add-ons the end-user must select. The RipBrace is installed and adjusted to a middle setting out of the box, requiring user customization for proper length of pull. The packaging includes a chamber flag and a basic multi-tool for adjusting the handguard and brace hardware, but no comprehensive armorer's kit.

Is the CMMG Banshee MK4 worth it at $1,531.99?

At $1,531.99, the Banshee MK4 is worth the investment only if you specifically need a suppressed, short-barrel 300 BLK platform and value its engineered recoil system over a standard AR build. This price gets you a complete, compliant pistol with a high-end trigger and ambi controls that would cost over $300 to add to a basic build, and a proprietary operating system you cannot replicate with aftermarket parts. However, a competent gunsmith could assemble a similar-direct-impingement 300 BLK pistol from quality components for under $1,100, sacrificing the radial-delay benefits. The value proposition hinges entirely on whether you prioritize mechanical optimization for suppression over pure cost-per-round; if you do, the Banshee is not overpriced for what it is.