This is actually an extension of a post I made from a week ago but information, I think, is important enough I wanted more people to read it. Basic story I had, new to me gunsmith, install a QD muzzle brake on my HK MR762. He commented that I needed to check suppressor alignment, when I got it, because threads felt "Loose". I asked here about the term. Turns out that loose is putting American threaded brake on metric threads. The pitch is the same (standard) but metric cut threads are approximately .03 inches shorter. This was discovered when the recoil of the fourth round fired out of my weapon threw the brake 40 yards out into the range at a 20 degree angle. There was, luckily, no bullet strike. Discovered when 5th shot was a super flyer. Article by Silencer Shop, https://www.silencershop.com/blog/p... of the thread location,a 1/2x20 thread pitch, lists some of the firearms that have this issue.