Hartshot, I believe all they have to do is thread the outside of the end of the barrel. All it is, is a tunable muzzle break.
By turning it you either lengthen or shorten the overall length of the barrel, and its weighted, the idea of the B.O.S.S system is to tune it to the load you are using so that when the bullet leaves the end of the barrel there is no vibration in the barrel, hence better accuracy. And they reduce recoil! Yes they work very well, if you spend the time to dial them in! Down side is they are [beeep] on your ears! VERY LOUD! Looks Pretty cool shooting them at night!
B.O.S.S. stands for....
Ballistic Optimizing Shooting System.
Winchester use to offer the same system, not sure if they still do or not?