I have always used 85 grain thunderheads on my carbon arrows. I bought the new and improved thunderhead 85grn. With the new broadheads they also tell you to use a U.B.A.R ring when using carbon or smaller dia shaft. UsuallyIjust used the locking ring and the rubber o-ring, has always worked fine before. Now they say locking ring then rubber o-ring then u.b.a.r ring. I put it on without the u.b.a.r washer and it fits like the old ones....blades are tight and secure.Never had thiswasher on any others I have bought in the last 6 years. Can't tell any size difference from the old ones, just the micro grooved ferrule is all. Didn't know if anyone can tell me if these u.b.a.r washers have to be on or not?
Thanks guys!
crutch