The CMMG Banshee MK4 5.56 SBR is a short-barreled rifle built around a 10.5-inch barrel, and at that length it is the shortest 5.56mm SBR CMMG offers. This Flat Dark Earth version rides on the Mk4 platform with a B5 Systems Bravo stock, an EML9 M-LOK handguard and CMMG’s full kit of ZEROED controls. A ZEROED SVB Brake sits on the 1/2×28-threaded muzzle, and the rifle ships with a 30-round CMMG magazine. It suits a shooter who wants a compact backpack or close-quarters rifle without giving up the standard AR-15 magazine and parts ecosystem.

Key Specifications

• The chambering is 5.56x45mm NATO, the standard AR-15 rifle cartridge with the widest ammunition selection.
• The barrel is 10.5 inches of 4140 chrome-moly steel with a 1:7 twist, a short length that keeps the rifle handy in tight spaces.
• The muzzle carries a ZEROED SVB Brake on 1/2×28 threads, a muzzle brake in the standard AR thread pattern.
• The stock is a B5 Systems Bravo on a six-position fastback receiver extension, so length of pull adjusts to the shooter.
• The handguard is a CMMG EML9 M-LOK, with M-LOK slots on both sides and the bottom for lights, grips and other accessories.

Frequently Asked Questions

What is the barrel length and how does it affect handling? The barrel is 10.5 inches. Paired with the adjustable Bravo stock, it gives a compact rifle that is easy to maneuver around vehicles, doorways and in a pack.

Do I need ATF approval to buy this? No. As of October 9, 2026, ATF no longer requires Form 4 approval, registration or a tax stamp for short-barreled rifles. It transfers on a Form 4473 with a background check through a Class 3 (SOT) dealer. State and local laws still apply. Taking an SBR across state lines still requires an approved ATF Form 5320.20.

Does it come with a magazine? Yes. CMMG lists one 30-round CMMG magazine with the rifle.

Buy the CMMG Banshee MK4 5.56 SBR, 10.5-Inch, Flat Dark Earth

As of October 9, 2026, this short-barreled rifle transfers on a Form 4473 with a background check at your Class 3 (SOT) dealer, with no Form 4 or tax stamp; state and local laws still apply. Order through CMMG‘s short-barrel rifles lineup and our Lubbock, Texas team will handle the transfer.