The CMMG Mk4 is a premium, highly versatile modern sporting rifle engineered on a true-to-spec AR-15 foundation. Designed for shooters who demand custom-tier quality straight out of the box, the Mk4 is built around a robust direct-impingement operating system that delivers exceptional balance, accuracy, and maneuverability.
Every Mk4 features a precision-machined billet 6061-T6 aluminum upper receiver paired with a rugged, forged 7075-T6 aluminum lower receiver. Upgraded with CMMG’s full suite of proprietary ZEROED™ ambidextrous components—including an upgraded pistol grip, trigger guard, and enhanced safety controls—the rifle offers seamless ergonomics for both right- and left-handed shooters. Finished in a highly durable, corrosion-resistant Cerakote coating over a free-floating 15-inch M-LOK handguard, the Mk4 stands as a dependable, all-purpose firearm ready for the range or defensive use.
| Specification | Details |
| Platform | Mk4 (Standard AR-15 Architecture) |
| Caliber | 5.56x45mm NATO (Safely accepts .223 Rem) |
| Operating System | Direct Impingement (Mid-Length Gas System) |
| Barrel Length | 16.1 Inches |
| Barrel Material | 4140 Chrome Moly Vanadium Steel (Medium Taper) |
| Barrel Twist Rate | 1:7 |
| Muzzle Device | A2 Birdcage Flash Hider (1/2×28 Thread) |
| Handguard | 15-Inch Free-Floating Aluminum M-LOK |
| Receivers | Billet 6061-T6 Aluminum Upper / Forged 7075-T6 Lower |
| Trigger Type | CMMG Single-Stage Mil-Spec Style |
| Furniture & Controls | CMMG ZEROED Pistol Grip, Safety, and Trigger Guard |
| Finish | Premium Protective Cerakote |
| Magazine Capacity | 30 Rounds (Ships with standard AR-15 PMAG) |
