I'll get some pics of the bore and post them as well. It's not horrible but there is some corrosion in there.
I also like to fire everything I own. Guns were meant to be shot! If this old girl is safe enough to shoot, I'll give it a go. I would guess I don't want to put full power charges through it right? I'll have to do some research and find some mild load data. I'm a reloader as well for lots of different pistol and rifle rounds but I've never done BP besides the pellets in the deer gun and shotshells in my damascus shotgun.
The rust looks 'scary' as is. My method for cleaning these is using a brass bore brush of proper size, chuck it in an electric drill and spin it at a low-normal speed. Use plenty of oil. You'll be amazed at how much crap comes out. Be sure to not scratch the bottom. Looks like the cylinder was dropped long ago, taking a nice nick out of one of the chambers.
If the nipples are out you may also clean the rear of the chambers.
Please upload a pic of both the rear of the cyl. Also a close-up of the nipples as these need checking. My recommended load: 20 grains FFG/FFFG BP, some filler and a .454 of .457 ball.
The barrel should be snug on the arbor, the cyl. rotate freely without excessive play, bbl cyl gap not exceed 0.02 inch and the wedge should fit tight in the slot, locking the barrel up nicely. Also check if the arbor has no wiggle in the frame.
If I even do decide to fire it, it won't be for quite a while as I don't have the means to start buying more shooting supplies right now.
I would advise to remove the nipples. If you need any help let us know.
I assume there's a special tool? I work in the auto industry and I have a tire valve stem remover that looks like it would work to remove those nipples but it's not a wrench-type tool. I highly doubt I could get enough torque on my small plastic-handle tool to get those nipples out. They look pretty rusted and crusted in there.