At its core the CMMG Mk4 RCE is an M4 upper receiver and an AR15 lower receiver – both forged from 7075-T6 aluminum. The barrel is a matte finished 416 stainless steel 16” barrel with 1:7 rifle twist. The Mk4 RCE weighs just 6.5 pounds unloaded and weighs 7.5 pounds with a fully-loaded 30-round PMAG. It is 33 inches long with the stock collapsed and is 36 3/8 inches in length with the stock extended.

The RCE includes an RKM14 KeyMod free-floating hand guard with a 1913 Picatinny rail on top. The KeyMod slots are found at the 3, 6 and 9 o’clock positions and offer shooters a low-profile mounting alternative to the M1913 Picatinny rail. For accessories that are not yet KeyMod compatible, users can purchase a separate CMMG 5-slot Picatinny adapter rail that can be easily attached to any of the KeyMod slots for optimal placement of the accessories.

The Mk4 RCE is equipped with a CMMG SV muzzle brake that helps to reduce recoil and increase muzzle control for quick and manageable follow-up shots. The muzzle break is built from nitride finished 4140 steel and is able to withstand harsh conditions while providing steady and consistent muzzle rise compensation.

CMMG Mk4 RCE Specifications:

Caliber: 5.56x45mm NATO / .300 AAC Blackout
Barrel: 16″ medium weight tapered profile, 416 stainless steel, 1:7” twist
Muzzle: CMMG SV muzzle brake, Threaded ½-28
Hand Guard: CMMG RKM14 KeyMod hand guard
Upper Receiver: Forged 7075-T6 AL M4
Lower Receiver: Forged 7075-T6 AL AR15
Trigger: Geissele Automatics SSA 2-stage trigger
Furniture: Magpul MOE Pistol Grip & CTR butt stock
Weight: 6.5 pounds (unloaded), 7.5 pounds (loaded with 30 round PMAG)
Length: 33 inches (stock collapsed), 36 3/8 inches (stock extended)
Magazine: 30rd Magpul PMAG
MSRP: $1,399.95

See more at

Up Next

Raytheon Wins $15M Excalibur Ib Contract

The U.S. Army has awarded Raytheon Company a $15 million contract modification for the...