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Banshee 300 Rifle
Mk4, 4.6x30mm


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Rifle, Banshee 300, Mk4, 4.6x30mm, NFA

FourSix™ SBR

Introducing an all new caliber to the Personal Defense Weapon market, the CMMG® FourSix™ SBR is the first AR to ever be chambered in 4.6x30mm. The CMMG 4.6x30mm magazine features 40-round capacity of a light recoiling round that offers great penetration at closer distances.

Built on the Banshee™ Mk4 platform, the FourSix SBR 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.

**All NFA rules apply** See linked CMMG Resource article for more information about short-barrel rifles.

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 Receivers, Handguard, Ripstock
Charging Handle CMMG Oversized Ambi
Pistol Grip Magpul MOE
Receiver Extension CMMG 6 Position Fastback buffer tube w/Ambi sling plate
Stock / Brace CMMG Ripstock
Trigger Type Single Stage Mil-Spec
Trigger Guard Magpul MOE
Safety Selector CMMG Ambi
Magazine 40rd 4.6x30mm magazine
Weight 5lbs 6oz (no magazine)
Length 26.9" (24.2" collapsed)

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