Curly - the Uberti's are the best of the repros.

I shot one for years, a civilian model 1860, with fluted cylinder.
At times, you have to open up the chambers a bit, to about .377/.378", then use a .380" ball. , making them a couple to 3 thousandths larger than the groove to groove diameter - THEN they really shoot well, as well as about any modern revolver, that is.

We've (Taylor and I)have also 'taken' to replacing the front blade ((soft)silver soldered into a longitudinal slot, not dovetailed) to a taller one as well as opening up the notch in the hammer nose, and perhaps moving it one side or the other a bit to get them shooting on the front blade.

Taylor is using a pair of ivory stocked, engraved Uberti's 51's for cowboy action. Unfortunately, the balls do not knock over all of the poppers, unless hit right at the top edge and even then, sometimes not.

Fun guns. A Walker, with the cylinders re-bored (1970's) that Taylor had, sold then recovered, still makes 1 1/2" groups at 25 yards, shot off bags. Seems to me, that one needed a .480" RB mould.

Some guys seem to have fun with them, unmodified, which is what it's all about. BUT - the accuracy is there if you want it.