When both my bro and I started with BP, we also had TC 50 cal. rifles with the then-standard 48" button rifled twist. Due to the shallow rifling, we found that even heavy loads would hold the rifling if a good tight fit were achieved between the ball and patch. We found that a .495" ball and at least an .018" patch was used, there was no limit where the ball would strip, but would maintain accuracy. We also found we had to smooth the crown's radius, to allow this tight combo without tearingthe patch. We used denim as it holds lots of lube, and with the locking stitch, is stronger than ticking.
: Our lubes ran from spit for target shooting, to vegetable oils, bear or mink oil for hunting. Nowadays, ther is Bore Butter, STumpy's Moose Snot, Lehigh and others which are all probably better than what we used back in the early 70's.
; All beginners to MuzzleLoading shooting, should purchase Ned Robert's "The MuzzleLoading Cap Lock Rifle" EVEN if you want to shoot a flinter. The knowledge the book will give, will answer 90% or more of the questions that come up concerning loading, shooting, cleaning, etc. Ned's writing, being a teacher and writer by trade, is well written, well laid out, and an excellent teaching tool. Hoepfully it is still available. If so, it is well worth the price, whatever that happens to be.