I was looking for a 5/8-24 muzzle brake for a 18" 6.5 Grendel build when I found this brake (Killer Innovations). They do them in 5/8-24 5.56 & .308 Figured I couldn't go wrong at 49.95, seeing I was real close to picking up other brakes which were twice the cost. I have been using the Rainier Arms XTC. Once I received the brake I was more than impressed with the design, machining and finish. One well designed/ manufactured brake at a great price. http://killer-innovations.com Here some pics I took of the brake. On my fluted #7 contour Lilja.