Gotta disagree with you KodiakBob.
The dif between XX75's, XX78's and X7's is pure marketing spin. 96K psi tensile strength to 105K psi tensile strength is an increase of 10%, but hardly significant. Wall thickness has a greater bearing on aluminum durability. Stay with the shafts with 18-20 thousanths wall thickness and you can't go wrong. I've got a dozen OLD gamegetters in 2018 that I've been shooting for years. Those are OLD gamegetters made from 6065 alum. Tensile strength on those old shafts was about 65K psi. Again, unless like others said, if you're hitting rocks, ain't much any shaft material is gonna help.