I use cast in mine. Here is the quirk with mine. Size to .429/.430, I get a sewerpipe looking bore and 5-6" groups at 25yds for the first 20rds, then it goes down hill quick past that as lead builds up. Size to .433, and I get 2-3" groups at 100yds and no leading. Last time out I fired 80rds and it took 4 patches run through the bore to clean it without any scrubbing or anything, so at least with mine, it was just a matter of me trying to shoot them too small. I would say try it and just make sure you slug your bore and shoot bigger than bore size, as has been said. I'm happy with mine.