My 1:9.5 twist rifles don't have any issue stabilizing 175-gr C&C bullets. If I was going to shoot something heavier/longer I'd probably use my Zastava (1:866). But I'd surely try it in one of my M70s as well just to see what it would do.
Remember the length of the bullet matters, and the 175 grain bullets can vary widely in this regard
For example, have you tried the 175 grain Hornady ELD-X in the 9.5 twist?
