I don't know what you intend to use the load for, target or hunting, but I've had good luck with the Sierra 55 gr GameKing HPBT in any 1:12 twist factory rifle I've tried them in. I use 26.0 grs of Varget, Fed 205M primers, and WCC military brass. I seat for a 0.015" jump. Check out http://stevespages.com/224_8.html for bullet weight and powder combinations. Also http://www.hodgdon.com/ and click on Reloading Data Center. - nhk