I'm looking at lyman 311359 mold and nearly everywhere I look it's listed as .309-.312, I don't understand how or why they would list a mold in that range of sizes. I'm pretty green at this but I honestly don't understand. I realize different alloys throw different sizes. But is that why? Or can I order a mold that drops .313 or is it luck of the draw? Does anyone know or should I just call lyman. As much as I have their products they're the only maker of a mold that I need.