CMMG makes some damn fine rifles, and it’s been a company willing to push the boundaries of the AR platform. From the Mutant, which blended the AK and AR, to the Banshee, which completely changed what a PCC can be. And today we are going to be talking about exactly that: How the CMMG Banshee modernized the AR-style PCC.

The CMMG Banshee series comes in hot with a multitude of calibers, configurations, and similar designs. The CMMG Banshee series comes in both pistol and short-barreled rifle variants in a swath of calibers.

What makes these little CMMG weapons different from any other AR-type PCC on the market? Well, it all comes down to the operating system. Most AR-type PCCs and submachine guns utilize a direct blowback system. Guns like the Aero EPC and the Colt SMG utilize this system, and it’s proven to be a very reliable means to make an AR-style firearm in an AR configuration.

However, there are downsides. A direct blowback system delivers more recoil than necessary. Most 9mm blowback PCCs have the same recoil as a 5.56 AR 15. Direct blowback requires a heavy bolt or heavy buffer and spring, or a combination of both. As such, these weapons get a little heavier than they need to be. They also make it tough to use more powerful calibers like the 10mm Auto.

Yet, the CMMG Banshee solved all of these problems with the invention of a radial blowback action.

The CMMG Banshee and the Radial Blowback Action

Blowback actions do not require a gas system, so most Banshees lack the traditional gas tube and block you see with AR 15 rifles. Direct blowback requires heavy bolts and springs to delay the opening of the bolt until pressure is low enough to safely do so. CMMG’s radial blowback action uses specialized bolts and chambers that allow the bolt to rotate and lock into the chamber.

The bolt lugs use 120-degree angles that lock into a specialized proprietary chamber. To unlock the chamber the bolthead has to rotate, and that rotation causes a delay. This delay allows the pressure to drop to a safe level before the bolt reciprocates. Because the delay can be initiated by this rotation, the system does not require a heavy bolt or spring. This also eliminates the hefty recoil PCCs with direct blowback actions also deal with.

It allows the guns to remain lightweight, extremely low recoiling, and be chambered in the widest variety of pistol calibers.

Gas-powered Banshees

Banshee-in-name-only is what I call a few of the other CMMG Banshee firearms. CMMG extended the lineup to include a 300 Blackout and 7.62×39 caliber option. However, these use traditional gas systems and not the radial delayed goodness that makes the Banshee great. I wanted to acknowledge that these guns exist, but also keep in mind they are not the subject of the article. Also, the 22LR Banshee does use direct blowback, and again it’s not what I consider to be a real Banshee.

Going Caliber Crazy

The CMMG Banshee firearms that utilize the radial delayed systems use a variety of what we consider pistol calibers and magazine designs. Predictably the gun utilizes Glock magazines, which are famously favored by being affordable, reliable, easy to find, and available in a wide variety of calibers and capacities.

Glock magazine-fed CMMG Banshee firearms come in 9mm, as well as 40 S&W, 45 ACP, and my favorite 10mm. The advent of more potent calibers like the 10mm makes the CMMG Banshee a bit different than most PCCs, especially when you consider how lightweight the 10mm variants of the CMMG Banshee are.

Beyond those common and capable cartridges, the CMMG Banshee also chambers the too-cool-for-school 5.7x28mm. Calling this a pistol cartridge doesn’t tell the whole story. It can be fired from a pistol, the most famous being FN’s 5.7 pistols. The Banshee even uses FN’s pistol magazine to feed it.

However, this cartridge is also used in the P90 SMG and is defined as a PDW cartridge. Not quite a pistol cartridge, but something between a pistol and rifle cartridge. The 5.7 is designed to offer more power than a pistol cartridge, a longer effective range, and better armor penetration. In the CMMG Banshee, you get an outstanding and very capable platform that still uses the radial delayed blowback system.

Going Live

The CMMG Banshee provides a very modern platform for those looking to dispense pistol-caliber pills for fun and defense. Like any AR, the platform is extremely ergonomic and very modular. It can be fitted with a wide variety of braces or stocks for SBRs, and lights and optics are all an option as well.

Users can build their own Banshees by purchasing the proprietary bolt and barrel with the proprietary chamber.

The CMMG Banshee has redefined what a PCC can be. It’s radical enough to make a big difference, but still offers what makes the AR platform a great gun.