I know that the Rugers in .41Magnum are generalized at 1:20 twist. I believe that holds true for the T/C also. I've got a Ruger Bisley from Davidsons that has a 1:16 twist in .41Magnum. It likes hard cast bullets over 250gr. Freedom Arms and DW also have faster twist barrels that I think are 1:16 or 1:16.5 in .41Magnum. These shoot the heavy .41s very accurately. Someday I'm going to make a list of all the .41Magnums and their twist rate. Just something else I haven't "gotten around toit" yet. :-D