As somebody already said, get #10 caps. I think you can get them from Cabela's and most sport shops can probably order you in a box of them.
As for the felt wads, Dixie Gun Works has them (as do some sports shops I have visited, too).
Also, use Bore Butter on the top as this helps cut down the BP residue fouling making reloading easier and cleaning faster.
I really like my Uberti Wells Fargo, which is the same model only without the loading rod. I mould my own .32 balls for it, but I used to use the buckshot, as in the suggestion that the other person made here, as well. Worked great then, should work great now.
The Doc is out now.