IMR 3031 is your huckleberry with 200gr. bullets, I'm using a Ken Waters load in my .35 Whelen which produces 3 shot cloverleaf groups @ 100 yds. IMR 4064 produces similar results with 225gr. bullets, these are my two powder selections with these bullet weights. When I got my Whelen back from rebore more than 25 yrs. ago i did extensive research and range testing which resulted in the selection of these two powders. I tried 180gr. bullets but they did not yield as fine accuracy as 200 & 225 grainers, always felt that 250gr. was more bullet than necessary for whitetails.
I've been pondering a Whelen so I'll have to remember that if I end up with one. In my 358 WIn, IMR 4064 typically gave me better accuracy with the 200s than 3031, which did give more velocity. IMR 4064 worked well with the 225 Sierra too. I don't remember trying 3031 so I may have to give it a try with that bullet. TAC or X-Terminator have also worked well with the 200s for me.
