Congratulations ! You have a superb muzzleloader ! I have one and my sons have one each ( three total) - all blued not Stainless. We use #11 caps or Musket caps. They work well with both. The one problem we had is failure to fire. The first pull on the trigger, it doesn't go off. The second pull and it does go off. The reason was our fault. We 'wonderlubed' the firing pin assembly. The lube gunks up the firing pin assembly enough to slow it down in cold weather and causes a failure to fire. I have since learned to use a dry lube on it only- with no problems since then. The only other caution I have is that you must remove the firing pin assembly and clean the inside of the bolt assembly after you are finished shooting for the day. I have used only Pyrodex RS (90 grains) and triple Seven (90 grains), shooting sabots 275 grains. The Pyrodex RS gave me better accuracy. I probably should lighten up on the Triple Seven to 80 grains. I would really like to try a non corrosive powder in this rifle, but I have four cans of Pyrodex leftover from an after Christmas sale at Wally World. I do not want to go to shotgun primers due to the many stories I heard about the 'crud ring' residue left in the barrel.
By the way, you can make an extra 'bolt shroud' by cutting up a 20 gauge shotshell hull to the right size and drill the vent hole in in. Use the shroud in bad weather only - as it drives more smoke into the bolt assembly.
Good luck with your rifle --It's a keeper !