CMMG Banshee 300 MK4 ‘FourSix’ Tactical AR-15-Type Pistol/SBR (Short Barreled Rifle): 40+1 Rounds of 4.6x30mm Firepower and Fun!

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By David Crane
david (at) defensereview (dot) com

November 17, 2021

Well, this one’s fun. It’s been over six and a half YEARS since DefenseReview’s (DR) published a piece on CMMG products, but this one caught our attention. Your humble correspondent was probably one of the first civilians to shoot the HK MP7/MP7A1 4.6x30mm PDW (Personal Defense Weapon) on US soil, and I REALLY enjoyed the experience. It’s a really fun little gun, and I love the design. So, the 4.6x30mm cartridge (and the MP7A1) holds a special place in my heart. Well, CMMG just announced their new Banshee 300 MK4 “FourSix” tactical AR (AR-15)-type pistol/SBR (Short Barreled Rifle), which gives you 40+1 rounds of glorious 4.6x30mm semi-auto firepower with which to plink steel and paper.

While the 4.6x30mm rounds may be diminutive in size, and lacking in stopping power on an individual-round basis, the CMMG Banshee FourSix gives you 50 ROUNDS total in the gun. And, since the cartridge is so easy to shoot, with very little recoil, you can pepper a target very quickly with a lot of rounds. Also, since the 4.6x30mm cartridge is essentially a miniature rifle cartridge, you’ve got a small 40gr (40 grain) rifle-shaped projectile traveling at around 1900-2000 FPS (Feet Per Second), and the rounds have very good penetrative capability on both soft and hard targets, especially if your using AP (Armor Piercing/Armor Penetrating) rounds, which we believe are only currently available to law enforcement and military customers.

DR’s primary concern at the moment is how reliable, durable and accurate the Banshee FourSix is, since both IT and its proprietary 40-round magazine are new. To assess those things, we’d want DR writer/contributor and chief new-product tester Jeff Gurwitch to run the FourSix at the range for us. Until then, let’s hope it works as advertised.

Editor’s Note: The reason Defense Review is listing the FourSix as a pistol/SBR, is that while it looks like it’s in SBR configuration in the promo video (see below), it’s being marketed commercially to civilians as a pistol on the CMMG website. We’re assuming CMMG will offer it both ways, but we’re not yet sure. So, we’ll try to find out.

Company Contact Info:

P.O. Box 369
Fayette, MO. 65248
Retail Phone: 660-248-2293
Dealer Phone: 573-875-2821
Sales Email: [email protected]
Tech Support Email: [email protected]
NFA Email: [email protected]
CMMG Facebook Page:

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CMMG Banshee 300 MK4 ‘FourSix’ Tactical AR-15-Type Pistol/SBR (Short Barreled Rifle): 40+1 Rounds of 4.6x30mm Firepower and Fun! by

About David Crane

David Crane started publishing online in 2001. Since that time, governments, military organizations, Special Operators (i.e. professional trigger pullers), agencies, and civilian tactical shooters the world over have come to depend on Defense Review as the authoritative source of news and information on "the latest and greatest" in the field of military defense and tactical technology and hardware, including tactical firearms, ammunition, equipment, gear, and training.

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