American Tactical Imports Muzzle Brake Rise Mitigation 5.56X45mm w/ Crush Washer Black. 56 HFS Muzzle Brake The HFS Muzzle Brake is the newest muzzle device from American Tactical Inc. Our ultra slim 0.750 inch design allows for easy work on your gas system without the need to remove the muzzle brake from the barrel. The large lateral ports combined with the smaller dorsal ports assist to reduce muzzle climb by as much as 95percent virtually eliminating muzzle climb when shooting. This reduction enables for more accurate follow on shots as compared to standard muzzle devices. Installation Instructions: Place the crush washer on the threaded end of the barrel with the concave side facing forward (towards the muzzle brake) Hand tighten the muzzle brake against the crush washer Tighten the muzzle brake until the top two ports are indexed top dead center on the barrel Check for tightness by attempting to remove by hand (do not over tighten tightening more than 1 full rotation can cause damage to the parts) Specifications for American Tactical Imports HFS Rise Mitigation Muzzle Brake w/Crush Washer 5.56X45mm: Manufacturer: American Tactical Imports Color: Black Caliber: 5.56x45mm NATO Fabric/Material: 4140 Steel Threads per Inch: 1/2x28 Length: 2.25 - in Included Accessories: Crush Washer Features: .750 inch Ultra Slim Design 0.5x28 Threading (Standard 5.56 barrel threading) 2.25 inch in Length Proprietary Slim Crush Washer Included Designed for 95percent Reduction of Muzzle Climb 4140 Steel 100percent Machined by American Tactical Inc. in Summerville SC Package Contents: American Tactical Imports HFS Rise Mitigation Muzzle Brake w/Crush Washer 5.56X45mm American Tactical Imports ATIHFS556MB: Muzzle Brake Rise Mitigation 5.56X45mm w/ Crush Washer Black