+1 for Dixie Gun Works, great customer service for my limited interaction with them. They also supposedly have a pretty cool store front in Union City, Tennessee if your ever in the area.
My dad had his CVA Big Bore .58 Cal stolen early this year. It was mainly used for deer hunting in Michigan during Black Powder season. He loved that gun, so he was hoping to get another one. He's looking at a Lyman today.
You mignt try Cain's Outdoors in Williamstown W.Va. The owner was an original partner of Mountian State Muzzleloader I believe, which was a huge black powder store. MSM is out of business now, but they used to be the go to place for anything black powder.