Velocity is a factor also. I was told 80 gr JLK's needed a 1-7 or 1-8 twist and they shot great out of my 1-9. The reason was the velocity, they were being push at 3550 fps. It would be easier for me if they would list what rpm range they shot best at and print the formula for rpms on the box. /ubbthreads/images/graemlins/grinning-smiley-003.gif Velocity X 12 divided by Twist X 60 = RPM
3,550 X 12 = 42,600
42,600/9 = 4,733
4,733 X 60 = 283,980 RPM's
2,600 X 12 = 31,200
31,200/9 = 3,467
3,467 X 60 = 208,020
Just My $.02 /ubbthreads/images/graemlins/grin.gif RR