If thefishing sinker lead is giving youmuch lighter balls from the same mold that threw the heavier ones, it's probablynot pure lead. Those sinkers may have been cast from wheel weights. An alloy in the lead could account for that blue sheen you were seeing also. Idon't think a hard ball will be any problem in a smooth bore. It's how they shoot for you that counts. You sure don't need to worry about expansion with a .62.