the only problems your going to have with that gun is recoil with heavy loads.. get ahold of veril and get some blue lube.. i used to shoot 400 grain bullets at 1900 feet per second (ruger 45-70)with hard cast , no dropping, had lots of leading until i whent to veril smiths blue lube. hes moderator on one of these columns. youll be able to shoot over 1900-2000 ft per second. you probably will need to test many powders, many crimps, differing lead hardneses to get accuracy..try some different primers too. you could hit it right off but different powders really make a diffence in accuracy.. .. the hardest lead is made by droppong antimony allow in water but you have to wait for it to harden and it will soften after good while. and some keep the bullets in the freezer.. your twist in that gun will alow you to use longer bullets but how long i dont know.. the 45-70 i had never shot well becouse i was using too long of bullets with the slow twist it had.. if you shoot a deer with a 458 hard cast at 2000 f p s in the lungs it may scamper away never to be found.. if you shot it with pure lead paper patch bullet at 1300 ft per second in the lungs or shoulder it will be like hitting it with a sledge hammer.. around circa 1900 or just before jacketed bullets came out paper patch was used alot for hunting loads, and was really getting going even for buffalo. my opinion only.. dave...