I've got a Brownings A-Bolt in 7MM mag that came with a BOSS. There's no doubt in my mind that it works. I'd work with my loads to a 1/2" 3 shot goup, and then use the BOSS to fine tune the load. Once the BOSS was set properly the groups would be as advertised. I'd get 2 bullets into the same hole, third bullet would figure "8" the group to a low 2, as in .2". Some bullets were tougher than others to tune, but everything I shot thru that rifle showed an improvment when working with the BOSS. YMMV.