Sharpshooter I have one of the 450 Marlin Pistols and it is a hand full for reloading data on it you can call Hornady they will send you info on it or go to hodgdons powder wed site they have it there listed under rifle loading data all I can say is get some gloves and keep your fingers away from the trigger guard and let her go its fun to shoot I use H 4198 51.0 grains and a 300 grain Hornady jhp and fed 210 primers but this is in my gun starting load for this powder is 38.5grains good luck. the load I use gets 1997 fps out of a 15 inch tube :grin: