I believe O'Connor's load, and the one I have used and liked, was 53.0/4320 with any 150 gr. bullet. Since then, I have had better luck with AA 2520 and Varget, but if you have 4320 it's still a good load.
forepaw
"Only accurate rifles (that are light enough to be carried by a middle-aged man in rough country) are interesting"
