I have loaded lee 1 oz slugs, used a blackpowder shot wad, over American Pioneer blackpowder substitute and have had some fun with it. They shoot slow and relatively accurate out of both smooth and rifled bores. The APP doesn't foul the barrel real bad like real BP does. I haven't shot anything other than paper.... I just leave the shell lip slightly roll crimped and glue a card wad over the top with a hot glue gun.
regards,
Gene