Ah yes, these's no answers, just more questions. What are you hunting with the bullets? Anyway, the old tried and true 4350 (either kind, IMR or H) ain't no bad place to start. I've killed one cow elk, several mulies, and a whole bunch of WTs with cup and core bullets. The velocity window of the .280 lends itself well to ordinary bullets. Nothing wrong with a little extra self confidence however.