Stoger’s M3500 series of shotguns delivers quality and performance at an unbeatable price. These ultra-reliable semiautomatic shotguns are equipped with Stoger’s proven Inertia Driven System – a simple yet reliable action that differs from gas-operated semiautomatics. The Inertia Driven System is composed of just 3 moving parts and eliminates the need for gas cylinders, O-Rings, and other complicated parts. Instead of using gas expansion, the Inertia Driven System uses recoil to cycle shells.