The SIG M400 Tread is an AR-15 platform with free-float MLOK handguard, 16-inch barrel, and SIG Sauer's enhanced flat trigger. A modern direct-impingement AR positioned at the value end of the SIG rifle lineup without sacrificing quality. Type: Semi-Auto Rifle Action: SA Caliber: 5.56 NATO Capacity: 30 Year introduced: 2019, USA Weight: 63.5 oz Overall length: 32" Status: Active Intended use: Tactical, Home Defense, Competition