Lead tin alloys age soften over time before stabilising.

http://www.lasc.us/Fryxell_Book_Chap...Metallurgy.htm



I've been casting some hollowpoint bullets, massive hollowpoints, with recylced air rifle pellet lead and they are too soft.

The nose section collapses as I put them through the lubrisizer.

I have some pure lead and some linotype and so think some experimentation is in order.