Designed specifically for the U.S. Marine Corps, the M4 shotgun was extensively tested and proven for maximum reliability, safety, function and performance. The M4 utilizes the unique Auto Regulating Gas Operating system (ARGO) which is a short-stroke, dual-piston design that is both simple and self-cleaning. Features a picatinny rail for easy mounting of optics, ghost ring sights for quick target acquisition, and nearly 20 years of battle proven reliability. Drilled and tapped receiver for scope mount, 5+1 capacity, 7.8lbs.