The SIG Sauer MCX Rattler with 5.5-inch barrel is one of the most compact pistol-classified 5.56mm firearms available, designed for maximum portability as a PDW-replacement or vehicle storage firearm. Type: Pistol Action: Gas-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 2018, USA Weight: 5.9 oz Overall length: 19" Status: Active Military use: Yes Intended use: PDW, Tactical, Vehicle Defense