So I have been mounting my new rings on my KM77VT's and am having a heck of a time breaking torx bits. They are a T10 size. I have so far broken 2 performance tool bits, and one Lisle bit. Does anyone know of a better bit that's out there? I was under the impression that Lisle tools were pretty good. I looked at the Leupold torx driver, but it's a T15. I need some help here!!!!