The CMMG Banshee Mk17 is a brand new entry into the Banshee pistol caliber carbine series, and no, it doesn’t take GLOCK magazines. It takes SIG P320 magazines.
The P320 has firmly cemented its place into the gun world by winning the Army’s MHS competition. It’s also being adopted across the country by police forces and seems to be popular in the civilian market, with even 80% Fire Control Groups being a thing. The Mk17 name is a reference to the M17, which is the military designation for the P320.
The guns in the Banshee series are not just your everyday average PCCs or 9mm AR pistols. Most PCCs rely on a direct blowback system that leads to increased recoil. The Banshee uses a rotary delayed recoil system, eliminating the need for a heavy bolt, buffer, or spring.
The delay allows pressure to fall in the chamber before the bolt unlocks and allows the weapon to cycle. This system has proven to be quite robust and reliable, and the Banshee comes in various configurations to include .45 ACP and 10mm.
The Banshee series also comes in three different series. Each series comes with various features and price points. The 100 series is the most basic model, the 200 Series has more features, and the 300 series is the premium model. The model reviewed in this article is the 300 series.
300 Series Features
The most prominent feature is the titanium cerakote, but there are nine other color options. The pistol brace is CMMG’s modified SBA3 Ripbrace model. This brace allows you to set the position you prefer and then pull the brace instantly to that position every single time.
We also get a QD port for a sling on the brace and a rear ambidextrous sling plate. The safety is also ambidextrous, as is the large charging handle.
Because the spring doesn’t need to be heavy and the charging handle is so large, the Banshee Mk17 is absurdly easy to rack and operate. The pistol grip is a Magpul MOE model, and the handguard is a free-floating M-LOK model with an integrated handstop. The barrel is also threaded so that you can add just about any can or muzzle device you want.
Lastly, there’s a discreet laser-engraved logo that says Banshee on the right side near the magazine release lever.
The Banshee Mk17 Ergonomics
That magazine release is a rather ingenious idea. It’s massive and set rearwards to ensure the magazine is locked in place. You can quickly eject the magazine with nothing more than your trigger finger. It’s easy to depress and has almost no resistance behind it.
The Ripbrace is fantastic and is quite stable and easy to use. It provides an excellent means of bracing the firearm and makes it quite handy. The ambidextrous charging handle and safety are nice touches, and I’ve come to appreciate the large charging handle and love the fact that it just glides rearward when used.
The gun is quite light and weighs than 5 pounds. The low weight makes the Banshee Mk17 very handy, and the short 5-inch barrel makes it easy to maneuver. This makes it an excellent house gun, especially for someone who might not be strong enough for a proper rifle or shotgun. Also, many of us can carry in a read position in a vehicle with concealed career permits because it’s a handgun. In Florida, I can keep this loaded and accessible in my truck as long as it is considered securely encased.
The short handguard gives you enough room to grip the gun, and if you choose, you can grasp the weapon by the magazine well and not lose much leverage.
That fancy rotary delayed blowback system does an excellent job of reducing the recoil commonly associated with blowback firearms. It has significantly less recoil than something like a CZ Scorpion, and the Banshee Mk17 weighs 2 pounds less than the Scorpion. As you’d imagine, the 9mm is a tame cartridge from such a big AR pistol, and muzzle rise isn’t an issue.
The Banshee Mk17 is a kitten, and you can fire quite rapidly ad accurately into a target. This kind of gun is made for close-range use, and it’s a brilliant weapon within 50 yards or so. Past 50 yards, and we start to get some substantial bullet drop from the 9mm cartridge. Within 50 yards, the gun is also quite accurate. The trigger is a mil-spec model that’s not fancy, but its also not a bad trigger. Mil-Spec isn’t a universal descriptor for the trigger, and the CMMG model is a refined example. It has no pre-travel, and it’s just a wall, then a snap.
Accuracy wise you can generate a 2-inch group at 50 yards with nothing more than a red dot and a hasty prone position. At 25 yards, I saw groups smaller than an inch. That’s an excellent degree of accuracy from a 9mm subgun wannabe. It’s more than most will ever need. The Banshee Mk17 is a decisive weapon inside of 50 yards.
I like to toss in wider varieties of ammo when I test a gun for reliability, but ammunition is not exactly easy to come by. I was stuck with a mixture of 115 grain SIG ammo, SIG M17 JHPs, and some classic 124 grain Winchester White Box loads. In the first 500 rounds, I was unable to make the gun choke. I even fired in a variety of weird ways, including a two-handed traditional pistol grip, one-handed, braced to my forearm, from the shoulder, and held outward in a quasi SAS style shooting position.
The Banshee never choked. It ate through it all without complaint or concern. The Banshee Mk17 is a ton of fun to shoot, and I want to spend a lot more time with the gun.
Specifications: CMMG Banshee Mk17 Pistol
Barrel Length: 5 inches
Overall Length: 18.9 inches
Weight: 4 lbs 10 ounces
MSRP: $1,549.95 (300 Series model)
Ratings (out of five stars):
Accuracy * * * *
As far as 9mm subguns go, this is one of the most accurate I’ve handled. It’s got a great trigger, and I find it an excellent and decisive firearm inside of 50 yards.
Reliability * * * * *
It eats everything without any complaint. Shoot it in weird positions or normal ones…it won’t choke.
Ergonomics * * * *
The gun is light, handy, and the controls are mostly ambidextrous. The magazine release design is brilliant and the Banshee Mk17 makes the best of the AR-15’s ergonomics.
Customization * * * *
Like an AR-15, you can do almost anything you want to it. You can Barbie it up nearly any way you want. One star off because the rotary delayed system relies on CMMG parts that can’t be replaced by aftermarket options. At least not yet.
Bang for Your Buck * * *
The Banshee Mk17 is an expensive firearm with an MSRP of $1,549.95, but it’s feature-filled and packed with excellent goods and handy add-ons. The 100 and 200 series are a good bit cheaper, too. The big downside is that the gun only comes with a single 21-round SIG P320 magazine.
Overall * * * * 1/2
The Banshee is a very well made PCC that has a lot of refinement and a great overall design. It’s low recoiling, accurate, fun to shoot, and for P320 users, you have a premium grade option should you want a weapon that can share mags with your pistol. The Banshee Mk17 is a very capable weapon that’s a lot of fun to shoot.