Just work up the load, for instance, load ten rounds with 2.5gr of powder, ten with 2.7, 2.9, etc to past where you think you need to be to make minor then shoot them over a chrono collecting the brass and looking at the primers. If the primers are starting to flatten stop and pull the rest of the ammo, if you make your desired power factor stop and pull the rest, if velocity starts to go down, stop and pull the rest. You get the idea.