I have never cast round balls myself as I am not really set up for it. I had a seasoned blackpowder guy make them for me at 1 part Linotype : 1 part pure lead. I verified that he dropped the round balls into water. I chose this alloy as I calculated it to have 6% Antimony (which is what the best commercial magnum shot made by Remington contains), as well as 2% Tin which should also increase the hardness. Most commercial buckshot from PR and BPI is notoriously soft and only contains 2%-3% Antimony, so I figured my choice had to be an improvement.
I did a quick Cast Boolits search and found the following excerpt:
“...Infact, your mix above, 50% Linotype/50% Pure Lead, is the "Recipe" for Hardball Alloy which is what most commercial reloaders have used for 30 years! It is actually around 15-16 BHN though.
It was designed back then as a replacement for Lyman #2 Alloy. It achieves the same hardness using less than 1/2 the Tin and at the time it was very economical since Linotype was being phased out of the printing industry and it was easy to find at bargain prices.”
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