If the mold is Clean, and HOT enough, then you have to consider molding technique. I found that you can't pour that lead into the mold too far from the pot, and with a bottom pour mold, you have to put the mold right UP AGAINST the spout, or you get wrinkled balls/bullets. When I used a dipper and a top pour mold, I had to hold the alum.Alloy blocks close to the molten lead, to keep the heat up, on both the mold and the dipper, or occasionally get wrinkled balls.
Finally, sometimes the hole in the cut-off plate, on the top of the mold is too Small in diameter to let you get hot lead into the mold Fast enough. Wrinkled balls are a result of the lead cooling before the ball is created. I have had this happen with Large Diameter Round balls and .45 and larger bullets/conicals. Pouring Hollow based conicals can be a real PITA for this reason, too.
I have drilled these pour holes larger- just another # drill bit size larger at a time-- and then used a center bevel cutter to re-cut the bevel on the hole in the cut-off plate. Both improve the speed at which the molten lead pours into the mold, and cure the wrinkled ball/bullet/conical problems.
Without being there with you as you cast, Its the technique issues that are most difficult to diagnose. You may nor may not be doing anything I have not done. Except, perhaps enlarging that hole in the cut-off plate. Just understand that with the suggestions you have received, the wrinkled ball problem can be cured.
Don't forget to raise the temperature on your pot. Don't be bothered about "frosted" balls. They result from the the lead being hotter than necessary, but they cast uniformly in weight, and are smooth.
I think that note from Lee Precision about the sprue lead staying molten on top of the mold for 3-5 seconds is as good a "barometer" as too whether you lead is as hot as it needs to be to get good casts, as anything I have ever tried, or observed over the years. I suspect your sprue is hardening in much less time.
I found that getting non-wrinkled balls or bullets was much harder with my usual casting temperatures when I first began to cast small caliber bullets and balls. For some reason, I was having difficulty keeping those mold blocks hot between pours, unless I set the blocks into the molten lead to warm back up before each cast. These were with the Lyman steel molds. The bottom half of the balls and bullets would come out just fine- smooth, and well filled. But, the top part, up right under the plate, would not fill correctly, or would have wrinkles right near the sprue. That is the mold that I first drilled open the hole on- altho its not been the last!
Years later, I met a man who was a professional bullet caster, and when we got talking about molds one day, and problems, I told him about this, and how I "cured the problem". He just smiled,and said, " Figured that out all by yourself, did you?"
He showed me half a dozen molds where he had changed the thickness of the cutter plates, and/or drilled out the pour holes. The only molds he had that I never saw altered were his Lyman and H&G gang molds, that poured 4-8 bullets at a time. ( Those 8-bullet molds were very heavy!) I had an opportunity to watch him use those gang molds one evening when He asked me over to talk about some legal matters while he was trying to fill an order for cast bullets. Since all I have ever used( so far) are single cavity molds, I got a very fine education, watching his molding technique, and quietly counting off the seconds he waited before he cut those sprues, and opened the molds. More important for my education was how long he warmed those molds back up before the next time he poured. He had 3 gang molds, and used them in rotation so that the blocks were hot enough by the time it was its turn to accept molten lead again. The other two were place on the top of his 20 lb. bottom pour pot. He also routinely added another ingot of lead to the pot after a double cycle of the gang molds. If any of these comments give you additional hints for changes in your casting technique, use them. :v :bow: :grin:
