After testing many rounds I have had best sucess with 24.0 grains RX10 powder, 40 grain Berger match bullet, Federal #GM205Match primers, Winchester brass using a Rem 700 Rangemaster 100 with 26" barrel. Other powders used H322, Varget, H414 but best results for me is the RX10 with the Berger bullets. Every rifle will shoot different so good luck.
In addition to the powders mentioned above, I use Hodgdon's BL-C(2) extensively in the .204 - one of my favorite loads is 29.5 grains of it behind a 40 gr V-Max.