Something that was interesting to me was, the shape of the bullet nose effected regulation. My Sabatti rifle was regulated with Hornady Factory 286gr spritzer, however it would print the left barrel about 2" higher than the right. I switched to a round nose and they became level at 50 yds. As to loads you might try H414 with a 286gr Woodleigh or Privi Partisan and Win/rifle primer. I used Hornady loading data to develop this load.
Bob