Personal-defense weapons sit somewhere between the assault rifle and submachine gun in terms of power, range, and capability. True PDWs like the MP7 and P90 are select-fire weapons made for close encounters. They offer more range than 9mm and can punch through soft armor quite efficiently. Due to infringements on the 2nd Amendment, we can’t own a true PDW, but we can own weapons close to their capabilities. The CMMG FourSix brings the 4.6x30mm to the civilian market, and all I can say is, “Finally!”


The 4.6x30mm

4.6x30mm rounds
(Courtesy of author)

The FourSix’s use of the 4.6x30mm round marks the first time we’ve seen a civilian-oriented weapon in the 4.6x30mm, and the first an AR chambers the cartridge. The little 4.6x30mm came to be due to the PDW project NATO put on throughout the early 90s and 2000s. The idea was to create a round that could outperform the 9mm in range and soft armor penetration. Two rounds were developed, FN’s 5.7×28 and HK’s 4.6x30mm.

The little 5.7×28 has seen its fair share of firearms produced, including rifles, pistols, and subguns, yet the 4.6 eluded the civilian gun owner. The Banshee MK4 FourSix finally gives us an option for those who are 4.6x30mm curious. More options are always better, and the 4.6x30mm might be the perfect option for you.

4.6x30mm rounds
(Courtesy of author)

At 100 yards, I saw four to 4.5 inches of drop, making it quite the flat shooter. For comparison, when I shoot 9mm at this range, I’m seeing a larger deviation of nine to 12 inches of drop depending on the round fired. The 4.6x30mm acts somewhat like a rifle round and tumbles when it hits the body. With most of the weight at the rear of the bullet, the round tends to tumble when it strikes the body and then fragment.

The 4.6x30mm penetrates to FBI standards and has become a favorite with SEAL Team Six in the MP7. They’ve put plenty of terrorists in the ground with the 4.6x30mm round.


Breaking Down the FourSix

The CMMG FourSix utilizes a classic AR-15 design that everyone knows and loves. The FourSix also utilizes an eight-inch barrel topped with CMMG’s own SV brake for even more recoil reduction. The barrel comes surrounded with an M-LOK compatible handguard for you to outfit your FourSix with lights, lasers, cupholders, etc.

The FourSix is a part of the Banshee series of firearms from CMMG. The Banshee series are short and sweet guns made to be effective close-range fighting weapons. Unlike most of the Banshee series, the FourSix comes outfitted with a direct impingement gas system instead of the radial-delayed blowback design. This translates into a smooth and reliable design.

CMMG FourSix
(Courtesy of author)

The magazines sport a fascinating and clever design that makes use of an injection-molded magazine of roughly the same dimensions as a standard AR-15 magazine. This allows users to build their own FourSix rifle with a standard lower and ensures magazine compatibility with AR-15 magazine pouches. The mags hold 40 rounds of 4.6x30mm and function with a standard last round bolt hold-open device.

CMMG FourSix magazine
(Courtesy of author)

Additionally, the weapon comes with ambidextrous safety and an ambidextrous, oversized charging handle. We also get the CMMG RipBrace that is an adjustable brace designed to be rapidly opened to a set point the user chooses on the receiver extension.


Why You’d Choose the FourSix

The FourSix grants you a very small weapon that’s well suited for close-quarter combat. This AR pistol brings the PDW home with the FourSix design. The 4.6x30mm outperforms the 9mm at longer ranges and gives you a round capable from one yard to 150 yards. The CMMG Banshee proved to be exceptionally accurate at 100 yards in the standing position and at 150 yards with a good supported position.

CMMG FourSix magazine and rifle
(Courtesy of author)

Hitting targets at these ranges proved easy, and more than just hitting them, the rounds easily land in the vital chest area of the target. When we moved up closer to home-defenses ranges, we also saw a big advantage with the FourSix Banshee. The gun has hardly any recoil; it handles like a loud rimfire rifle.

Rearward recoil and muzzle rise are silly easy to control and allow you to very easily fire rapidly and accurately. Running combative drills like the El Presidente (modified) or the failure stop and box drill proved the weapon could be used quickly and easily. I was scoring extremely fast times and my shots were landing exactly where I wanted them.

The FourSix provides less recoil than a 9mm and much less muzzle rise. The increased control makes it a very handy personal-defense weapon that blasts away with absolute ease. Shot placement matters more than anything else, and the FourSix allows you to easily place those rounds where you want them.


Going Steady

The CMMG Banshee Mk4 FourSix is a fascinating platform that brings the 4.6x30mm home. The handy little platform makes it easy to send lead downrange out to 100 yards while still excelling at extremely close quarters. The CMMG Banshee series has long delivered fantastic firearms, and the FourSix lives up to that relationship.