The ARGO system is a unique, short-stroke, dual-piston design developed to cycle every 2 3/4” and 3” round still in military service without requiring user adjustment. This compact action features dual stainless steel self-cleaning gas pistons located just ahead of the chamber that act directly against rotating bolt, eliminating the need for the complex linkages found in other gas systems. The pistons only move about half an inch to completely cycle the action, making the M4 faster and smoother-running than other autoloaders. And because the gas port is located just forward of the chamber—where the gasses are hotter and cleaner—it results in less fouling and less cleaning.