So it was 50F today so I decided to have a go at some casting. I tried my new single Old West .45 cal 547 gr Silhouette mould, and my dual cavity Lee 312-180 mould. Started out doing good with the .45's but I was observing some odd inclusions along the sides of the bullets. I had no idea how to diagnose this issue. I tried different heat settings on my LEE pro pot, really didn't help, then I tried different flow adjustments, that seemed to help a little bit but still not perfect. I was keeping my moulds hot in a cast iron pan with propane heat. Turns out I believe my moulds were simply too cold. I experiemnted with heating up my moulds with a propane torch and then working pours and this definitely helped smooth out the surfaces of the finished castings. I think I have all my heat and flow settings adjusted well. I also have a better feel of how hot I need to keep the moulds to allow a nice consistent pour. When my moulds are hot enough a easy tap on the sprue plate gets it open. When my moulds are cool it takes a few brisk thumps to get it open. This is definately a "feel" type learning experience. I was getting very frustrated early as I thought I had a heat or flow issue, but turns out it was all mould temp. The big 547 gr mould is made of brass and it seems far more tolerant to varying mould temp to get a nice surface. The LEE 312 mould is more challenging to get the perfect "pour" . Here's a few pics of "mould too cold" and "mould hot" pics :
Nice hot mould:
Cold mould: