Okiecruffler,
Yes, the 1 in 60 twist is for round ball use.
The classic book about muzzleloading rifles is Roberts, Ned, The Muzzle Loading Caplock Rifle, Granite State Press, Manchester, New Hampshire, 1940. It covers muzzleloading hunting and target rifles. There is a short history of some of the old American makers. There are hunting stories by a fine raconteur. Roberts goes into practical rifle shooting, along with black powder lore and techniques. He covers care of antique rifles. Much of the information is available nowhere else. This is a jewel of a book that you'll return to every so often; it's so well written so that it approaches being literature. It has been reprinted many times, by many publishers. I wouldn't be surprised if it is still in print; one way or another, it is not difficult to secure a copy.
BTW, Ned Roberts was the man responsible for the development of the 257 Roberts, he was a gun crank's gun crank...
Only John Chapman's (rare) book, The American Rifle, Appleton, New York, New York, 1848 approaches the Roberts book in comprehensiveness. To the best of my knowledge, this book has been reprinted only once, by Clark, Manchester New Hampshire, in, I think, 1941. Roberts was responsible for this reprinting.
Among books written by living authors, look for any of several by Sam Fadala, according to your area of interest.
There is a lot to be gleaned by simply looking through back copies of the Dixie Gun Works catalogs, as well as old Bannerman's Catalogs.
I can recommend books covering more narrow interests if you're interested.
Bob