Why don't you find out what twist rate the Hawkens barrel is? Then we can go from there. Could be anywhere from 1:28 to 1:66 but probably a 1:48. You can use a patched cleaning jag/rod and see how much the rod turns in one length of the barrel if you need to.

Actually for a buddy of mine who is going to get back into shooting after a long hiatus due to divorce, etc. His .50 Hawken survived but he cannot recall what loads he once used. I found an old Lyman blackpowder handbook laying around, but it has no info on saboted bullets. Seems that most of those have a 240 gr. 45 cal. bullet. Any help appreciated...I'm a BPCR shooter but have no experience with muzzleloaders.

Thanks

Write or call Thompson Center and tell them you have a Hawken and give them the serial # if it's a TC product. They will send you a booklet with load data and lots of information on care and cleaning of your gun. (no charge)

His "old Hawken" probably has a rifling twist too slow for sabotted bullets - it's probably 1/48" or slower, for round balls and short, full bore-size conicals like the Maxi-ball.