CMMG Banshee Mk4 .300 Blackout Review ::

First Impressions


The CMMG Banshee Mk4 is compact and lightweight, but it also feels like a solid gun that could take some punishment. (Photo: Ryan Domke/

I knew that the Banshee was ultra-compact but didn’t expect how well-built and solid it was going to feel. It’s light, at just over a mere 5 pounds, but it feels like you could throw it off a roof and not have any damage occur (don’t try this, just to be clear). You’ll find the standard PMag to go along with it inside the box but not much else aside from the lock and literature, which is really all you need. 

As I alluded to earlier, the Banshee features plenty of quality parts. From the internals and the controls to the furniture, you can tell that CMMG definitely put some thought into them all.

Specs & Features

CMMG Banshee Mk4
The safety is ambi, and the upper and lower are made from different T6 aluminum billets. (Photo: Ryan Domke/

Starting with the “bones” of the gun, the 8-inch barrel with a 1:7 twist works great for this size of an AR pistol. It’s not CMMG’s smallest, which is actually a 6.5-inch barrel, but I prefer the 8-inch option for better handleability and accuracy. The upper receiver and lower receiver are both made out of durable T6 aluminum, with the upper being billet 6061 and the lower being forged 7075. They are topped off with an ambidextrous charging handle and safety selector.

CMMG Banshee Mk4
The charging handle is ambi. (Photo: Ryan Domke/
CMMG Banshee Mk4
The Magpul grip is a nice touch. (Photo: Ryan Domke/

From an aesthetic and furniture perspective, I don’t have any real complaints. While FDE seems to be increasingly popular these days in the AR world, I’m still a sucker for the blacked-out look. The minimalistic and adjustable CMMG RipBrace fits well for the build, and the
Magpul MOE grip is a solid upgrade from the standard A2 style. 

CMMG Banshee Mk4
RipBrace pistol brace is minimalist and just right for the fit and size of the gun. (Photo: Ryan Domke/
CMMG Banshee Mk4
CMMG makes a shorter version, but I rather like the 8-inch barrel. I do wish it came with a hand stop. (Photo: Ryan Domke/

The one thing I do feel that’s missing is a hand stop of some kind on the bottom of the handguard. With shorter barrels, I always prefer to have a hand stop for extra safety. 

Caliber: .300 AAC Blackout
Capacity: 30 rounds
Length: 23.7 inches
Barrel Length: 8 inches
Barrel Twist: 1:7
Weight: 5.1 pounds

Reliability & Accuracy

I was excited to hit the range with the Banshee, and I quickly put 180 rounds through it over a couple of range trips. All 180 rounds were
Ammo Inc. 150-grain FMJ and cycled flawlessly. I ran a few drills that required me to shoot single shots and three-round bursts. Then, of course, I had to do a mag dump or two. Not a single issue. 

CMMG Banshee Mk4
I found the gun to be plenty accurate for its size, and I had no issues with running ammo through it reliably. (Photo: Ryan Domke/

The Banshee didn’t come with any iron sights, so the accuracy has a lot to do with the optic you choose. I happened to have a Swampfox Liberator II and a Northtac Ronin P-12 laying around, so I tested it with both and was pleased. By the end of the first magazine, I was able to shoot a 2-inch grouping at 40 feet at my local indoor range. 

Afterwards, I took it over to a friend’s house to shoot outdoors on his property, where we set up a couple 6-inch and 8-inch gongs at 50 yards. I had no problem ringing those gongs at a quick rate of fire. I wouldn’t normally be shooting an AR pistol much farther out than that anyways, so I’m happy with those results within 50 yards. 

Pros & Cons

CMMG Banshee Mk4
The size is great and very wieldy, but you’ll notice the gun did not come with any iron sights. (Photo: Ryan Domke/

No gun out there, at least that I’ve ever encountered, is completely void of cons. You also need to remember that pros and cons can be subjective, so just because some of these may be true for me, you may disagree.

•    Upgraded furniture finishes the build nicely
•    Lightweight, compact design makes maneuvering easy
•    Lower recoil than expected
•    Reliable
•    Non-proprietary mags    

•    On the pricey side
•    No hand stop 
•    No iron sights 

CMMG Banshee Mk4
That controllable recoil may owe something to the compensator, but a lot is owed to just the overall quality of the CMMG build itself. (Photo: Ryan Domke/
CMMG Banshee Mk4
The gun doesn’t come with many extras in the box, but a PMag is always a nice addition to find. (Photo: Ryan Domke/

In my opinion, the pros far outweigh the cons. You can always wait to find a deal, and you can add backup sights and an aftermarket hand stop if you’d like. The Banshee reminded me of the
Springfield Saint pistol that I shot recently, only the Banshee has a 1-inch shorter barrel. They share similar features and upgraded furniture, and both seem to be very reliable.

Final Thoughts

CMMG Banshee Mk4 .300 Blackout Review :: is written by for

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