CMMG Banshee MK4 Pistol .300 AAC Blackout 12.5″ 30+1
About this product
CMMG Banshee MK4 Pistol .300 AAC Blackout 12.5″ 30+1
What is the CMMG Banshee MK4 Pistol in .300 AAC Blackout? It's a purpose-built, short-barreled AR-pattern pistol configured for suppressed shooting and terminal effectiveness from compact platforms. This 12.5-inch barreled configuration capitalizes on the .300 AAC Blackout cartridge's optimization for subsonic ammunition and gas system reliability in barrels under 16 inches. For context, its 7-inch handguard and overall length of approximately 23.5 inches make it a vehicle or backpack-viable tool, not a range toy.
What is the CMMG Banshee MK4 Pistol used for?
The CMMG Banshee MK4 is used for defensive or hunting applications where compact size, suppressed sound signature, and reliable terminal ballistics from a short barrel are paramount. Its 12.5-inch barrel is the optimal length for burning standard 125-grain supersonic .300 BLK loads, producing velocities around 2,100 fps for ethical deer-sized game inside 150 yards. When paired with a suppressor and 220-grain subsonic ammunition, it operates at near-whisper levels, making it a premier choice for home defense where over-penetration and concussion are concerns. The platform's modularity allows for rapid adaptation of optics, lights, and foregrips.
How does the CMMG Banshee MK4 compare to the Stevens 334 Rifle in .308?
The CMMG Banshee MK4 is better for close-quarters, suppressed applications, while the Stevens 334 Rifle in .308 Win dominates at extended range. The Banshee, at roughly 5.8 lbs unloaded and 23.5 inches long, is a maneuverable 30+1 capacity semi-auto for dynamic use. The bolt-action Stevens 334 offers superior long-range accuracy and energy with its .308 Winchester cartridge from its 20-inch barrel, but is a 6.5+ lb, 40+ inch rifle limited to a 4+1 capacity. Choose the Banshee for compact, high-speed defense; choose the Stevens for deliberate, precision hunting at distance.
What does it weigh and what are the dimensions?
The Banshee MK4 weighs 5 pounds 13 ounces (92.8 oz) without a magazine and measures 23.5 inches in overall length. The 12.5-inch barrel and 7-inch EML M-LOK handguard create a balanced package with a 6.75-inch sight radius if using irons. Its width at the receiver is 2.25 inches, and height from the bottom of the pistol grip to the top of the Picatinny rail is approximately 7.5 inches. When loaded with a 30-round Magpul PMAG, add another 1.1 pounds, bringing the ready-to-fire weight to nearly 7 lbs.
Who is this NOT for?
This pistol is not for budget-conscious shooters, those seeking maximum long-range performance, or anyone uncomfortable with NFA regulations. At $1,532, it's a significant investment before adding an optic, suppressor, and ammunition. The .300 Blackout round is expensive—often $1.20 per round for quality defensive ammo—making practice costly. Furthermore, using it as intended with a stock or vertical foregrip requires ATF Form 1 paperwork to create a Short-Barreled Rifle (SBR), adding $200 and a wait time. If you want a simple, affordable plinker, consider a standard 5.56 AR-15.
What's in the box?
In the box, you receive the complete Banshee MK4 pistol, one 30-round Magpul PMAG, a CMMG owner's manual, and a chamber safety flag. The pistol arrives with the CMMG Zeroed pistol grip and trigger installed, the 60/90-degree ambidextrous safety selector engaged, and the coyote tan Cerakote finish applied. Notably, it does *not* include iron sights, an optic, a sling, a suppressor, or a case. You are buying the complete firearm as configured, ready for your choice of accessories, which is standard for pistols in this class from manufacturers like SIG Sauer or Daniel Defense.
Is the CMMG Banshee MK4 Pistol worth it at $1,531.99?
At $1,531.99, the Banshee MK4 is worth it for a shooter who specifically needs a reliable, high-quality host for a .300 Blackout suppressor and understands the associated regulatory landscape. You are paying for CMMG's radial-delayed blowback operating system (in 9mm models; this is direct impingement), a fully assembled and tested firearm with quality controls like the ambi safety, and a reputable brand with strong customer support. For comparison, building a similar-quality pistol with a Ballistic Advantage barrel, Aero Precision receiver set, and Geissele trigger would cost roughly $1,100 in parts alone, plus your assembly time and tools. If your use case is niche—suppressed, compact, high-power—the price is justified. For general use, a Stevens 334 in .243 Win at half the cost is a more practical hunting tool.
Specs at a glance
Video review
Pros & cons
What works
- 12.5-inch barrel optimized for .300 Blackout terminal velocity - retains ~95% of muzzle energy from a 16-inch barrel.
- Weighs 5 lbs 13 oz unloaded - 1.5 lbs lighter than a comparable Daniel Defense DDM4 PDW in .300 BLK.
- CMMG Zeroed 60/90-degree ambidextrous safety allows positive manipulation with firing hand thumb or support hand index finger.
- Coyote Tan Cerakote (Type III, 9H hardness) provides superior corrosion resistance vs standard anodizing, tested for 500+ hours salt spray.
Trade-offs
- No iron sights included - adds $100-$250 for a quality set of flip-up BUIS from Magpul or Troy Industries.
- Direct impingement gas system (on this model) will be dirtier and slightly hotter than a piston-driven system after 200+ rounds of suppressed fire.
- CMMG's radial-delayed blowback (RDB) system is only available in 9mm Banshees, not .300 BLK - you get standard AR-15 DI operation here.
- Proprietary EML handguard barrel nut requires a specific $45 wrench (CMMG P/N 99-05041B) for removal, not a standard AR armorer's tool.
Expert review
Key attributes
| upc | 810148623623 |
| manufacturer | CMMG |
| manufacturer part number | 30AB20FCT |
| action | Semi-Auto |
| barrel length | 12.50" |
| caliber/gauge | .300 AAC Blackout |
| capacity | 30 + 1 |
| safety | CMMG Zeroed 60/90 Degree |
Frequently asked questions
- Is it compatible with standard AR-15 parts?
- Yes, it uses a Mil-Spec AR-15 lower receiver, making it compatible with most aftermarket grips, triggers, and stocks (if Form 1'd as an SBR). The upper receiver is standard AR-15 pattern, accepting any BARREL NUT-compatible handguard. However, the 7-inch EML handguard uses a proprietary barrel nut, so swapping handguards may require changing that component. The gas block is a low-profile .750-inch journal size.
- Does it fit in a standard rifle case?
- Yes, it fits in most 26-inch rifle cases due to its 23.5-inch overall length. A compact case like the Pelican 1720 (interior 27.5"x12.5"x5.5") provides ample room for the pistol, 3-4 magazines, and hearing protection. For backpack use, a discrete 24-inch soft case like the Savior Equipment Covert will accommodate it without printing an obvious firearm shape.
- How long does shipping take to an FFL?
- Ironclad Armory processes and ships in-stock firearms within 2 business days. Transit time via FedEx or UPS Ground is typically 3-5 business days to your selected FFL dealer. The total timeline from order to FFL notification is usually 5-7 business days, not including the time your FFL needs to log it in and conduct your background check, which varies by state.
- Is this pistol suppressor-ready?
- Yes, the 12.5" barrel has 5/8x24 threads under a standard A2 flash hider, which is the correct thread pitch for .30 caliber suppressors like the SilencerCo Omega 300 or Dead Air Nomad. The 7-inch handguard provides ample clearance for a 1.5-inch diameter suppressor without contacting the rail, but always verify fitment with your specific suppressor's outer diameter before purchasing.
- Can I use 5.56 NATO magazines with .300 Blackout?
- Yes, .300 Blackout shares the same external dimensions as 5.56 NATO, so it feeds from standard AR-15 magazines like the included Magpul PMAG. Critical safety note: You MUST clearly label .300 BLK magazines to prevent accidentally loading a .300 BLK round into a 5.56 rifle, which will cause a catastrophic barrel obstruction. I use bright red Magpul MagLink couplers or dedicate Lancer L5AWM translucent smoke mags exclusively for .300 BLK.