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Banshee 300 Pistol
Mk4, 4.6x30mm


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Pistol, Banshee 300, Mk4, 4.6x30mm


CMMG® is proud to announce the release of the FourSix™, the first ever AR to hit the civilian market chambered in 4.6x30mm. With an impressive 40-round magazine capacity, light recoil and great penetration at close distances, CMMG’s FourSix is here to reimagine the Personal Defense Weapon.

Built on the Banshee™ Mk4 platform, the FourSix pistol features AR15 controls and modularity. Best of all, the patent pending CMMG 40RD 4.6x30mm Magazine will seat into a standard AR 15-sized magwell, which means users can pair their existing AR15 lower receiver with a CMMG FourSix upper receiver and magazine.

What is 4.6x30mm?

First introduced in 1999, the 4.6x30mm is known for its pairing with the Heckler & Koch MP7. By design, the 4.6x30mm is a relatively small and lightweight cartridge with minimal felt recoil meant to compete with the 5.7x28mm. There has never been a 4.6x30mm-chambered firearm released in the U.S. civilian market until now.

Ballistically the 4.6x30mm round is very similar to the 5.7x28mm round in the sense that it is a high velocity, flat shooting projectile that has great penetration, but where the 4.6x30mm will hold an advantage is in your pocketbook. Due to the difficult barrier of entry for ammo manufacturers, the 5.7x28mm round currently and will always cost more than the more affordable and easier to manufacture 4.6x30mm round.

Lifetime Quality Guarantee

All CMMG products are backed by our Lifetime Quality Guarantee against material or worksmanship defects. Learn more.

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
Barrel Twist 1:5.9
Muzzle Device CMMG SV Brake
Muzzle Thread 1/2"-28
Gas Port Location Micro
Gas Block FourSix specific .750
Upper Receiver Forged 7075-T6 Aluminum M4 Type
Lower Receiver AR15
Hand Guard CMMG RML7 M-LOK
Finish Cerakote
Charging Handle CMMG Oversized Ambi
Pistol Grip Magpul MOE
Stock / Brace CMMG RipBrace
Trigger Type Single Stage Mil-Spec
Trigger Guard Magpul MOE
Safety Selector CMMG Ambi
Magazine 40rd 4.6x30mm magazine
Weight 5lbs 6oz (no magazine)

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