So are you going to get the 11mm mold? I will also say that if you can harden the bullets to 8 or 8.5 BHN this should help with groups. Those bullets should have been right at 8.5 BHN.

I got it in the mail today Ron. I have a Lyman 45 cal Maxi-ball mold that I was going to take the handles off. But alas they didn't fit. I had to go and but a set of mold handles for it. They should be here on Friday.
I have a bunch of ingots that I made from assorted chilled shot I had lying around for years. I had dropped the ingots into cold water after they solidified. The hardness on them is 12.7 but likely due to the quenching. I will probably melt these with pure lead on a 1 to 1 ratio.

a 1 to 1 ratio is going to still be very hard. Mixing lead without a tester is a good way to ruin lead. If you don't have a hardness tester I would go 5 to 1 or maybe 4 to 1.

I broke off a piece of ingot and remelted it and after about 4 hours of setting I checked the hardness again and it was 10.7. The 12.7 previous result was likely the result of a water quench. I think a 4-1 mix will be fine.

What will you be hunting with it? If Bear, 4:1 may just soften it up a bit too much. Take it to 3:1 for bear and you will have a fairly hard bullet to bust shoulders and it will still open up some. If whitetail, then 4:1 would take it to about 7.3 to 7.5 air cooled for about 2 weeks. Those would be some nice buck crackers. Still hard enough for deer shoulder if that's the only shot you have but soft enough to open up on ribs.

The bullets I sent him are about 8 to 8.5 BHN. That hardness is enough to plow through any black bear that lives in the lower 48 lengthwise. Harder lead is not needed or desired.
Your formula for hardness makes absolutely no sense. I don't know how you do the math with your lead but your math don't match my Cabine Tree hardness tester. 4 parts soft lead and one part hard lead is not going to be 7.3 to 7.5 BHN. No way in heII. What number are you using for the hard lead in your equation?

Age will harden alloy as well. If you do all the sizing fresh you should be okay. But I have never tested the 11mm bullet harder than about 9 bhn.

I was going by his numbers on the other lead he mixed up idahoron, not the hardness of your bullets. If you go by his results indicated at 12:7 water quenched. Which, if mixed with a pure lead, you will still have the antimony from the chilled shot. If that shot is as old as I imagine, since he said he'd had it around forever, it will have a very high antimony content. That reaction calls for a higher mix. Remember idahoron, shot made back 20-30 years ago was very hard with a high antimony content. Which is why I told him to mix higher for a softer content.

One thing I have found to be absolutely the truth When mixing alloy especially lead shot you can NOT just use math to get a hardness. It doesn't work. Some shot has higher levels of antimony. Real old shot used fairly pure lead then added the alloy, Some used reclaimed shot. Your numbers simply do not equate to a hardness factor as a guideline for hunting, especially one that can be reproduced and tested for repeatable results. I have been at this way to long to be fooled with your numbers or saying simply that 4:1 mix of an alloy is simply too soft for bear.
You said that 4:1 would soften it up too much. That is a number that is unknowable with the information that is at hand. There is way too many variables when shot is used. And he isn't sure if the hardness was quenching or if it was age hardened.

I guess I don't see where your saying to mix at a higher rate of soft? I see you are agreeing with him, only if bear is not the game of choice. Again I disagree with your input. And the reason I am is because there is simply not enough information to say that this piece of lead is exactly this hard. One way to mess up some good soft lead is to mix it without a hardness tester.