I have nothing but good things to say about the Tanner molds I have. A .550 mold from him drops a .550 ball about 99% of the time. As said in other posts, it depends on the casting material. I try to use pure lead in my casting, but occasionally some hardcast bullet lead gets in the mix and will drop a slightly smaller ball. I recently ordered a .345 ball mold for an heirloom .35 caliber long rifle. A .340 was sent by mistake. Once notified of the error, it was repalced with the correct mold in record time. Good people to deal with. Hopefully the son will keep the business going.