Until recently, all my lead for casting has come from WW and range scrap. When I was doing it about 1e yrs ago, I used to just melt SO and CO WW together, and cast from that. Never had any issues with that alloy. Now I sort my CO and SO into separate buckets for making ingots of each separately. I also hit a scrap yard and got some lead sheet, cable sheathing, and other soft lead. I made ingot from that already. I don't do black powder or muzzle loader balls. I load and cast for the following handgun and rifle (9mm, 38spl, 357 Mag, 44 Mag, 45ACP, 500 S&W, 223, and 30-30). So I know I'll need to harden the soft stuff up a little for a lot of my uses. I have a couple bags of Rotometals Superhard alloy nuggets, and some of their hardball nuggets. I don't use them for anything, but had them on hand for this purpose. How would I figure the correct amount to add to a 20lb Lee pot of soft? I also have several lbs of Pewter I made in 1-2oz disc ingots. So the tin I have on hand as well. Wanting something around 14-18 BHN. That seems to cover most of what I shoot, shot a lot in that range before through most of my stuff with no issues.