The CMMG Banshee
The Banshee line has a breathtaking variety of rifles and pistols. They are divided into basically two groups: one using a fixed ejector to expel pistol cases and similar, and the other using a traditional bolt-face ejector. Many of the pistol-caliber Banshees use pistol magazines, but the Mk4 9mm models use an altered P-Mag to run 9mm cartridges and others.
Related Review: CMMG Banshee Mk4 – Screaming Good Fun in .300 Blackout
An incredible assortment of firearms can be had within the Banshee line. Whether .22 LR or heavy-hitting 8.6 Blackout, you can find a model to fit your purposes. Configurations vary widely as well, with both short-barreled rifle and pistol options with and without the bureaucratically incorporated arm brace.
Aside from all the different configurations, CMMG has an interesting color palette. With a half dozen or more Cerakote colors, you can pick something more standard or make a statement.
Features
Colors and configurations aren’t all that set the Banshee apart. The Banshee comes with additional features that put it above its competitors. Some useful traits such as an ambidextrous magazine release will be helpful for left-handed shooters, and an enlarged right-side mag button makes it easy to smash when you’re moving quickly.
I like the 45-degree safety and the semi-low-profile selector, though some of my carbine comrades felt it was too low profile. CMMG’s Zeroed charging handle provides a dual locking feature, much like popular aftermarket models.
The lightweight handguard is M-LOK compatible and offers a variety of accessory mounting. The Fastback buttstock is quickly deployed when you want to extend it – more on that later.
The .300 Blackout
The .300 Blackout has become a popular chambering for AR-pattern rifles. Perhaps the most important draw of the cartridge is its utility in subsonic shooting. Subsonic cartridges operate below the speed of sound, and when suppressed, they are movie-quiet. Because of its low velocity when shooting subsonic, the .300 BLK does well with short barrels. This makes it a great choice for AR pistols and SBRs like those in the Banshee lineup.
The model we are looking at today uses a full-length 16-inch barrel. I'll get into it more later, but I'd prefer it in an SBR format – although that means jumping through more government hoops.
My personal feelings for the .300 Blackout are simple: the whole point of the cartridge was to shoot heavy bullets at subsonic speeds from a suppressed AR-style rifle. Once you deviate from that specific purpose, it seems to lose a lot of its novelty. If shooting the cartridge without a suppressor or in its supersonic configuration, it has few advantages over ballistically superior options.
Range Prep
Since the .300 Blackout isn’t what I would consider a long-range cartridge – few would – I set the rifle up for short-range shooting. With a likely maximum shooting distance of 200 or less yards, I decided that mounting my Eotech Vudu 1-6 riflescope would be more than enough scope for the Banshee. I mounted it with a cantilevered mount for proper alignment.
As I mentioned, this gun would shine only with a suppressor involved. I grabbed my Anechoic 35 suppressor, threaded a 5/8x24 thread cap into the breech of the suppressor, and screwed the assembly onto the muzzle of the Banshee.
Related: Anechoic Demos Innovative, Versatile AnechoX Suppressors for 2025
All that was left was to grab a few boxes of ammunition. I went with some Hornady selections of both super and subsonic. I know I mentioned that subsonic is king, but some out there simply must know, so I’m duty bound to try some supersonic ammo as well.
Shooting Time
Shooting the CMMG Banshee took us into the snowy winter mountains. The cold fluffy snow made the already quiet report of the rifle sound even softer. Of course, because I had to, I shot some supersonic ammunition to start. As expected, it all ran flawlessly.
The Banshee is a traditional direct-impingement AR and uses the traditional buffer and tube. Direct-impingement guns typically seem to be a bit gassier than piston-operated guns, but I experienced minimal suppressor backpressure with the Banshee.
The rifle’s light construction made it handy to maneuver, though in the cold, the aluminum parts were unfriendly to the skin. I like the rifle’s minimalist buttstock, but I’m not sure I like the one-way lock. By that I mean the collapsible Fastback stock can be pulled to the rear without needing to disengage the lock. That makes it very quick to expand the rifle. The downside is that if you use it on any position less than fully extended, you run the risk of pulling it farther out during manipulation.
The controls on the Banshee are top notch. Like other CMMG products, the Banshee comes with high-quality parts such as the trigger, safety, and other operational controls. This made shooting the Banshee even more pleasant.
Accuracy & Reliability
As expected, I saw better accuracy from the supersonic ammunition. I say “as expected” for a couple of reasons. Subsonic ammunition is often a little trickier to get consistent. In my experience, it is harder to customize ammo to the rifle’s tastes when loading subsonic.
To add to that issue, the Banshee’s 16-inch barrel is much longer than the Blackout needs for subsonic ammo. The longer barrel seems to exacerbate the variations in the subsonic loads. I feel the subsonic ammunition would do much better accuracy-wise with a shorter 10-inch barrel.
For all those same reasons, I wasn’t particularly surprised when we saw a couple of malfunctions while shooting subsonic ammunition. Some subsonic loads don’t have quite the gas pressure curve to reliably function the action of the rifle.
I am confident that it would be easy to find a subsonic load that reliably functions in the Banshee. I would even load one myself, because it is simply too fun and entertaining to shoot the gun with as little noise as manually running the action.
Pros & Cons
I think I’ve already touched on most of the cons of the rifle, most of which are more about the intricacies of the .300 Blackout than the Banshee itself. That and my personal preferences seem to be the only things I could mark against the Banshee and its design.
On the positive side, there is plenty to go over. This is the fourth or fifth CMMG product I’ve had, and as always, it is high quality. The fit and finish of CMMG’s guns seems to be above average, like its quality Cerakote colors and paint jobs. CMMG’s own furniture is more than adequate, and not the typical cheap stuff you have to replace.
