Thanks Carl, something like an RST 7/8 oz or 3/4 oz with #8 shot? I'll look for where I can buy them. I have RST 2 1/2 in 1 oz shells. Will probably try them if I can't find the 7/8 or 3/4 oz loads.
Black Powder is my default choice cause I have it and clean my old guns carefully after shooting them. Also, bought the gun (remember cut down to 18 1/4 barrels) thinking I would shoot it in the BP category in Cowboy Action.