If you want to shoot the traditional patched roundball, you'll want a barrel with slow twist rifling, no faster than one turn in 48 inches, preferably one turn in 66 or even 72 inches.
There are some traditional styled rifles that have fast rifling twist suitable for bullets, usually one turn in 28 inches.
The Lyman Great Plains rifle is available in a round ball twist and is more true to the actual rifles made by Hawkin than the TC Hawkin rifles are.
Pedersoli also makes a large variety of traditional and historically accurate long rifles.