The Benelli M4 Super 90 is the U.S. military-issue combat shotgun, designated M1014 Joint Service Shotgun. It uses Benelli's unique Auto-Regulating Gas-Operated (ARGO) system — two short-stroke piston rods positioned just ahead of the chamber — rather than the long-stroke or inertia systems used by competitors. The M4 operates reliably with less-lethal rounds, buckshot, and slugs without adjustment. Type: Shotgun Action: Semi-Automatic Caliber: 12 Gauge Capacity: 5 Year introduced: 1998, Italy Weight: 240 oz Overall length: 40" Status: Active Military use: Yes Intended use: Military, Law Enforcement, Tactical, Home Defense