Thanks for the replies guys. mehavey, very useful links. GP100man, (hey, I'm one too!) your link does have more data for IMR 4227 in 357 than Hodgdon's website but no data for the heavy bullets in 357 and nothing for Ruger-only 45 Colt
I think I have IMR specific data from Hornady so I guess I'll start there. I'm just curious if the Australian imported IMR 4227 is for sure the old H4227, in which case using that data would be no problem. Hodgdon needs to just come out and say one way or the other on its website. They already post identical data between the Hodgdon and Winchester powders that are identical.