The M400 Tread Patrol adds law enforcement-specific features to the standard M400 Tread — a shorter 14.5-inch barrel with permanently-attached muzzle brake to achieve Title I length, and a enhanced M-LOK handguard for duty accessories. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2019, USA Weight: 7.1 oz Overall length: 32" Status: Active Intended use: law_enforcement, patrol, duty