Temperature Doc, Whether the mold is Aluminum or steel doesn't seem to matter. What does matter is the temperature of the mold. The lead temp should be stabilised by the pot. Put the mold on top of the pot so that it is the same temp as the lead. after pouring the lead should take a short time to solidify. If it takes too long the mold is too hot. If it solidifies to quickly the mold is too cold. It takes a while to get the rhythm down so that the mold is the same temp for each pour.
I realise that this is elementary information, but I have found that to get consistent results, the temp must be the same for all pours. The problem comes from shrinkage in the mold. Also I always drop my round balls into a tall can of cold water to get the shrinkage rate the same.
I have used Hornady balls in my .50 Hawken and have had pretty fair results with them. I am still in the process of tightening up my groups though.
