beleg2
Try casting at a higher temp. It can be a bit of a balancing act keeping the mold/lead at the proper temperatures for good casting. I have a sponge handy to cool my molds a bit if the get too hot. I also use a casting thermometer and try to keep the pot at the same temperature thru out the casting session once I determine a good casting temperature for the mold/alloy I am using. It is not as easy to cast with pure lead as it is with alloy. I do not use bullets which cast with major flaws but I know others that do. I actually weigh each bullet and discard any that greatly deviate from the "mean" bullet weight of that session.