Unless it is from the Fox Ridge custom shop all TC Hawkens no matter the caliber are 1 in 48 twist. White Mountain Carbines and some of the inlines had faster twist from 1 in 28 to 1 in 38
In a TC Hawken 50 one should get pretty good accuracy with a .490 ball, thick patch(.015-.20) and 70-80 grains of black.