I know this is somewhat counter-intuitive, but velocity doesn't seem to have a whole lot to do with stability. If it did,rounds with lower velocities would need very fast twists andfaster calibers would have slower twists. There is very little differencebetween them, inmy experience.

Another exampleI would point to would be the 107 Sierra VLD bullet in the 6MM caliber. In a .243,this bullet needs a 1:8.5 twist to be stable. A 1:9 is right on the edge - 1:10 you are out of luck. My 6MM-284 can push the heavier bullets at least 300 fps faster than a .243. If the RPM theory was true, I should easily be able to get this bullet to work with a 1:10 twist in the bigger caliber at 10% higher velocity. But it don't work that way. Bullets hit the target sideways just like they did in the .243 with a 1:10 twist.