Overview: Since 1998 the Benelli M4’s ARGO® dual-piston system has set the standard for rock-solid, real-world reliability. The M4 EXT builds on that legacy with targeted enhancements for modern tactical use — bigger controls, extended capacity, and improved modularity. Lightweight, battle-proven, and engineered for mission adaptability, the M4 EXT is purpose-built for operators who demand consistent function in any environment. Key Features: -ARGO® Auto-Regulating Dual-Piston System: Proven, low-maintenance operation across a wide range of loads and conditions.