[JLA]

Not at all. its the total length of the bullet that makes it require a specific RPM, and Bullet RPM is a fuction of velocity and rifling pitch.

Take the 165 Hdy IB I listed above VS the 180 gr Failsafe also listed above. The failsafe requires 13.2 twist (180 gr bullet measuring 1.303" at 2700 fps, which is .30-06 velocity for that weight) and the IB requires 13.4 twist (165 gr bullet measuring 1.312 at 2800 fps, which is also .30-06 velocity for that weight) and the Failsafe has almost twice the bearing surface because it doesnt have a Boat tail. Now slow them both down in reduced loads to 2500 fps and the FS requires 12.7 and the IB requires 12.7, so internal ballistcally speaking they are equals in thier requirements as far as barrel twist is concerned.