CMMG Banshee MK4 5.7x28mm 5in Pistol, 32rd

Description

The CMMG Banshee MK4 5.7x28mm 5in Pistol, 32rd is a compact AR-platform pistol built for close-quarters work. Chambered in the flat-shooting 5.7x28mm cartridge, it uses a 5-inch barrel and CMMG’s radial delayed blowback system to keep recoil light and cycling smooth. This pistol accepts standard AR15 lower parts and CMMG’s 32-round conversion magazines, giving you a familiar platform in a fast, maneuverable package.

Manufacturer	CMMG
Model	Banshee MK4
Caliber	5.7x28mm
Barrel Length	5 inches
Capacity	32 rounds
Operating System	Radial delayed blowback, semi-automatic
Receiver Material	7075-T6 aluminum (per manufacturer specs)
Finish	Hardcoat anodized
Weight	4.9 lbs (per manufacturer specs)
Compatibility	Standard AR15 lower receiver geometry; CMMG 5.7x28mm conversion magazines
Condition	New

Key Features

• Radial Delayed Blowback System — Why it matters: This design slows the bolt’s rearward movement just enough to reduce felt recoil and muzzle rise, letting you stay on target for faster follow-up shots.
• 5-Inch Barrel in 5.7x28mm — Why it matters: The 5.7x28mm round delivers high velocity and low recoil from a short barrel, making this pistol ideal for tight spaces where every inch of maneuverability counts.
• 32-Round Magazine Capacity — Why it matters: With a full 32 rounds on tap, you spend less time reloading and more time shooting, whether at the range or in a defensive scenario.
• Ambidextrous Controls — Why it matters: A reversible charging handle and ambidextrous safety selector let left- and right-handed shooters run the gun without fumbling for controls.
• Optics-Ready Receiver — Why it matters: The upper receiver is machined with a flat top and mounting holes for common reflex sights, so you can add your preferred red dot without a gunsmith.

Who It’s For

This pistol is built for the shooter who values speed and compactness in a familiar AR platform. If you train for home defense, run drills on a short-range course, or simply appreciate the flat-shooting nature of 5.7x28mm, the Banshee MK4 fits your hand and your style. It’s also a solid choice for anyone who already owns AR15-pattern rifles and wants a pistol that shares parts and manual of arms.

Pros & Cons

• Pro: Radial delayed blowback cuts recoil noticeably compared to direct blowback 5.7 pistols.
• Pro: Uses standard AR15 lower components — triggers, grips, stocks (if you later SBR it) are all off-the-shelf.
• Pro: 32-round magazine gives you serious firepower in a small package.
• Con: The 5-inch barrel limits velocity somewhat compared to longer 5.7 rifles, though the cartridge still performs well at typical pistol distances.

Comparison: CMMG Banshee MK4 vs. Zev Technologies OZ9 vs. LWRC SMG 45

Feature	CMMG Banshee MK4	Zev Technologies OZ9	LWRC SMG 45
Caliber	5.7x28mm	9mm	.45 ACP
Barrel Length	5 inches	5.2 inches	6.5 inches
Capacity	32 rounds	17 rounds	25 rounds
Operating System	Radial delayed blowback	Striker-fired (locked breech)	Delayed blowback
Weight	4.9 lbs	1.6 lbs (pistol only)	5.8 lbs
MSRP	$1,623.95	$1,799.00	$2,199.00

The Banshee MK4 splits the difference between a traditional handgun and a PDW. It offers higher capacity and lower recoil than the OZ9, and it weighs less than the LWRC SMG 45 while still delivering a flat-shooting round.

FAQ

What magazines does the CMMG Banshee MK4 use?

It uses CMMG’s own 5.7x28mm conversion magazines, which are designed to fit standard AR15 magazine wells. A 32-round magazine is included with this pistol.

Is the CMMG Banshee MK4 compatible with standard AR15 triggers?

Yes. Because the lower receiver uses standard AR15 geometry, you can swap in any mil-spec or aftermarket trigger group. Just be sure to use CMMG’s specific hammer for reliable ignition with 5.7x28mm ammunition.

Can I mount an optic on the Banshee MK4?

Yes. The upper receiver is drilled and tapped for common red dot footprints (RMR, Docter, etc.). You’ll need the appropriate adapter plate, which is widely available.

What is the effective range of a 5-inch 5.7x28mm pistol?

With quality ammunition, you can expect reliable accuracy out to 50-75 yards. The 5.7 round retains enough velocity at those distances for defensive use.

Is this pistol legal in my state?

We ship nationwide to all 50 states, but some states have magazine capacity restrictions. Please check your local laws before ordering.

• ✅ Nationwide delivery (all 50 states)
• ✅ Ships 1-2 business days
• ✅ 30-day returns
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Last updated: April 2026