I found an interesting site... Mountain Molds makes custom bullet molds, & part of the bullet mold calculator lists suggested twist rates

I "built" a couple of interesting bullets ( 5 or 6 different profiles n weights between 500 & 550 grains ), & my twist rates varried from 1 in 42" to 1 in 46"

here is a link to the calculator... I'm currious if others have seen it & or agree with the suggested twist rates ???

http://www.mountainmolds.com/

click on line bullet design, & choose your caliber... I thought it was pretty interesting...

if I go up to 650 grains, the twist rate moves up to 1 in 37" with the same bullet profile