I've used mostly BL-C(2) in the .204; according the the first published data I saw it came the closest to factory loaded velocity but I haven't actually run any over the chrony. With 40gr bullets I can regularly shoot 1/2 MOA groups with my loads, although I tried 5 or 6 other powders and was able to get similar results I stuck with the BL-C(2) because it meters great and goes into the cases easily. Win748 is very similar and I've used it as well. Other good ones for me were Varget, H322, and H335. I haven't messed around much with the 32gr bullets, as my rifle seems to shoot the 39/40s better.