I haven't done a lot of boolit casting, and my interest is in casting pure lead (I actually use 1% tin) for airguns (.257 cal and up).... I only recently got a thermometer, and I'm still getting used to using it and trying to determine the optimum temperatures.... Today I was casting .358 cal Lee aluminum molds, the 125 gr. FN and the 150 gr. RN.... I cast the heavier ones first, at between 700-750 degrees, and even after the mold was warmed up, I was getting a bit of wrinkling.... The bullets were well filled at the base, with only about 10% discards.... but when I was sorting them I noticed that most had a few small wrinkles.... Too cold, right?....
When I cast the 125 gr., I raised the temperature gradually, and as I did, the bullets just kept getting better and better.... I wondered how far I could go before seeing any frosting, and even at 950 only some small areas near the base showed any dulling.... I backed the temperature down to 850, and cast most of the bullets at that temperature.... When I sorted them, I had a few of the early bullets that looked like the 150 gr. with a few small wrinkles.... The ones that had a dullish area near the base seemed to also, in general, have a slight flash on the edge where it looked like the sprue cutter had shaved the edge slightly.... as least I think that was primarily on the ones cast at over 900.... Basically, however, the 125 gr. (mostly cast at 850) were far superior in appearance to the 150 gr. which were cast at 750....
My question is this.... I see in the recent survey that the largest number of people case between 700-725.... Is that for alloys with a significantly lower melting point than the nearly pure lead I am using?.... Is there any reason I shouldn't cast at 850?....
Bob