Based on your experience with the .35 Whelen, which powder IMR4064 or RL15 is your preference when shooting 200-225gr. bullets. Please lets keep replies specific to the question I am asking and based on your own actual in the field/on the range experience with these powders and bullets. I am not interested in what any gunwriter or loading manual says. Thanks for keeping this in mind.

GW,

after building a 338/06, I had no real reason to build my desired 35 Whelan.... they were pretty interchangeable...

That being said, I can say with those two bullet weights in the 338/06, using both 4064 and good ol RL 15, they have been pretty much interchangeable.. both giving stellar performance for accuracy and velocity...

I am sure the Whelan guys will reflect the same experiences...
both being excellent cartridges and definite steps up from an 06.

RL-15 worked for me with 200 grain for any type.
I also use IMR3031.

GW--I load for several Whelens. IMR4064 with 200gr HSP and both IMR4064 and R-15 with 225's. Just depends which rifle likes which powder the best accuracy wise. Pretty close velocity wise in 700's and 7600's.

R-15 produced a tad more velocity with the 225 TSX and 225 Northforks in a 700KS that was used to take a good Alaskan Brown Bear a couple of years ago.

WN

RL 15 is what my 700 Classic prefers. 220 grain Speer or 200 grain round nose Sierra.