I would like to know if my one in 9.25 twist rate 7 mag will shoot the 175 grain eld x bullets. Hornady says 1 in 8.5 is best
Depends on your altitude, for one one thing. If you have the bullet specs you can plug in the numbers here and see:
http://www.bergerbullets.com/twist-rate-calculator/
It shoots in a true 1-9 twist but rifle barrels vary and bullets don't always follow the rules. Test it out and I would also shoot some into some type of media to see if they have a tendency to yaw after impact. If any question the 168s are very good and don't give up much to the 175s.
Then that's what you should enter where it says "altitude."
If you can’t stabilize the 175, consider the 162.
It kills, too.
P