I've got a great article on it. Peter Alexander wrote it and made the barrel at Colonial Williamsburg with Wallace Gussler. I dig it out for you. It is step by step.
If you can find the Gunsmith at Colonial Williamsburg video, you can watch Wallace Gusler forge and rifle a barrel. It is an impressive piece of craftsmanship. I do have a copy of the tape, but I've lent it to a friend. If you would like I can send it to you when I get it back.