NEW 4.6x30mm Banshee AR Pistol by CMMG (Hands-On)

CMMG just dropped a major announcement this week: they are introducing a new-to-the-AR chambering: 4.6x30mm! This cartridge was initially developed by H&K for the MP7, but is now available as a part of CMMG’s Banshee AR pistol lineup! In this story we’ll get hands-on with this new platform.


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About the Four Six Banshee

CMMG’s Banshee AR pistol and SBR platform spans numerous chamberings including 22LR, 5.56, 300 BLK, 9mm, 45 ACP, 5.7x28mm, 4.6x30mm, and many more.

Above: CMMG Banshee chambered in 4.6x30mm with Rip Brace, with Cerakote Charcoal Green finish, shown with reflex sight and suppressor (not included)

Technical Specifications

  • Platform: MK4
  • Caliber: 4.6X30MM
  • Operating System: DIRECT IMPINGEMENT
  • Barrel Length: 8
  • Barrel Twist: 1:5.9
  • Barrel Contour: MT
  • Barrel Material: 4140CM, SBN
  • Muzzle Device: CMMG SV BRAKE
  • Muzzle Thread: 1/2-28
  • Gas Port Location: MICRO
  • Gas Block: 0.750 NON-ADJUSTABLE
  • Upper Receiver: FORGED 7075-T6 ALUMINUM M4 TYPE
  • Lower Receiver: FORGED 7075-T6 ALUMINUM AR15 MIL-SPEC
  • Finish: CERAKOTE
  • Charging Handle: CMMG OVERSIZED AMBI
  • Pistol Grip: MAGPUL MOE
  • Stock/Brace: RIPSTOCK or RIPBRACE
  • Trigger Guard: MAGPUL MOE
  • Safety Selector: CMMG AMBI
  • Magazine: CMMG 40RD 4.6x30mm Magazine
  • Weight: 5lbs 6oz
  • Overall Length: 26.9”
  • Collapsed Length: 24.2” 

In order to bring 4.6x30mm to the Banshee platform, CMMG invested in the following components:

  • 4.6x30mm barrels
  • Tuned bolt carrier group with 4.6 boltface
  • 40 round magazines for 4.6x30mm (also available in 10 round)

What’s In the Box

Above: Banshee Four Six box contents (additional magazine shown, only one included)

The Four Six Banshee includes the following:

  • Banshee 4.6x30mm AR Pistol upper+lower
  • One 40 round magazine
  • Gun padlock
  • Instruction sheet

4.6x30mm 101

Above: 4.6x30mm (left) and 223 Remington (right) cartridges side by side

4.6x30mm is a cartridge that was designed in the late 1990s for the H&K MP7 platform. Similar to 5.7x28mm, the 4.6x30mm features a smaller diameter bullet, slightly different case rim, and other minor differences.

Here’s a side by side comparing 4.6x30mm, 5.7x29mm, and 223 Remington:

What kind of ammunition is available for 4.6x30mm? How difficult will it be to reload 4.6x30mm? These are questions I’ll be looking into in the near future!

Shooting the Four Six Banshee

For this testing, I used Fiocchi factory 40 grain 4.6x30mm ammunition:

I thought shooting this new Banshee would be fun, but I was surprised at how well I liked shooting this AR pistol at steel targets!

If you’ve shot an AR pistol chambered in 223/5.56, you know there’s a fair bit of recoil, and a TON of muzzle flash. Not the case with 4.6x30mm! This Banshee was very easy to keep on target, and I could have shot this thing literally for hours, it was that fun!

Things really got fun when I screwed on a suppressor!

The Omega 300 suppressor did a great job of keeping muzzle blast down to a minimum. There’s still the supersonic crack, but not bad at all. Good stuff!

Here’s the velocity data we picked up from the chronograph:

We saw higher velocity (1965 fps average) compared to Fiocchi’s advertised 1900 fps. I’m guessing that this is because of the 8″ barrel on the Banshee compared to the 7″ barrel on the H&K MP7. Plenty to ring steel with, or even take down a coyote (or similar animal). I also wouldn’t rule this AR pistol out for self defense!

What’s Next

I’m really having fun with this Banshee Four Six. Next I’m thinking to look at:

  • Ballistics comparison in-depth  (comparing to 5.7x28mm and 223/5.56)
  • Reloading the 4.6x30mm

If you’re interested in the Banshee Four Six, check it out at

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