The SIG MPX is a closed-bolt 9mm carbine with a short-stroke gas piston system. The closed-bolt design provides improved accuracy and reliability over open-bolt SMG designs. Available in carbine configuration with a 16-inch barrel for civilian legal rifle classification. Type: Semi-Auto Carbine Action: SA Caliber: 9mm Capacity: 30 Year introduced: 2015, USA Weight: 57.6 oz Overall length: 35.5" Status: Active Intended use: Competition, Law Enforcement, Home Defense