I melted about twenty pounds of scrap odds and ends yesterday and cast a few bullets to measure hardness over time. After about twenty-four hours, samples average 9-10 BHN on my LBT tester. I'm hoping for a final hardness of about 12 BHN as this hardness seems best for my .357 loads. I normally use a mix of known hardness, so I seldom check day-to-day hardness. Will the 9-10 BHN bullets get appreciably harder? Of course, I can always adjust the mix one way or the other.