My Accurate mold would not cast round bullets. I started checking and using a ground 123 block, could see daylight across the 4 cavity mold. I began lapping the halves, I did not remove the pins, wish I knew how they were put in, but worked both surfaces until I could not see any light between them. Last casting proved they were casting much better that before, half the round-out in diameter than before.
Taking a piece of stock, then boring a bunch of holes, and expecting them to not warp, is not good practice. Metals need to relax after work. I wish I could have removed the pins to lap, I would have a great mold.