Hi, Tony:
I can go up to 37.5 grains of IMR 3031 with the 200 grain Core-Lokt, a Winchester WLR primer and a Remington case. I tried H322 but you can't fill the case with it and it's position sensitive. IMR 4320 wouldn't be bad except that my rifle's point of impact shifts about 4" just as I get up to speed. This shift happens about the 34 grains point with 3031, so I'm well above it with the 37.5 load. I figure that if I use 4320, I'll see that monster buck some cold morning, the load will perform like it's a grain short and I'll shoot under it. I haven't tried any other powders since the 3031 load is fast and accurate in my rifle. I've got 16 types of smokeless and 3 types of black here and I don't want any more.
Your rifle might be the opposite of mine.
Bye
Jack