BHN is the name of the game. Pure lead is 1-2 BHN
Hardcast at rated 15-17 BHN. Anything harder is lino type and used to richen soft lead into harder rounds. At 25 BHN Lino is too head to use by itself.
How to: Real easy. When you pour pure lead in comes out 1-2 BHN.
Any higher and the impurity content is too high.
When I make my rounds I have a bowl with ice water in it, and a towel u7nder the ice. You just drop them in the ice, it hardens the outer shell to 15-17 BHN. Right where you want them for cast shooting.
Using Wheel Weights as the control. (6-9 BHN).
When you get into paper patches, then the fun begins. You go back to 2-3 BHN and incase the slick sided projectile with 2 turns of paper.
I just run cold water in my quinching bucket I use a Hardball mix similar to The ol’Lyman #2 and then after i pour wait a few seconds then drop in the water bucket I go by the look of the sprue on top. As soon as it has a certian solidified color I lop them off then open the mold dropping thd bullets in water. . I find mine are hard enough to completely pass side to side through a buck deer and run in my .460 with near zero lead in the barrel with hot loads