I wasn't going to comment here...but what the heck, I rarely hold back my thoughts here
(except for politics/religion)...LOL.
.
So you just found out your 5:1 alloy is 10.6 BHN. What does that tell you?
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Let me give you my thoughts:
Linotype should be 4/12/84
(4% tin, 12% antimony, and 84% lead)
If you add 4 parts of pure Lead, you'll get about 1/3/96, which is about what COWW
(clip-on wheel weights) alloy is, although COWW typically has a little less tin. I mention this because it seems most of the interweb chatter is other people asking what scrap they can blend together to get a alloy near COWW. Much of the talk from many long time casters is in reference to COWW, because that was "thee" most abundant scrap source for many years. and by happen stance, that is also the main reason I think COWW is a good all-around bullet alloy. I've got a bunch of it
(more than a ton.) From my experience, it seems to be able to do most things (shooting-wise) adequately. If you want more specific info, or just want to know more, you should read the metallurgy chapters in bullet casting books/manuals. After you get somewhat more of a base knowledge of bullet metallurgy, you'll be answering your own questions, or able to ask more specific questions that the seasoned shooters here can offer, better, more specific answers.
Here are a couple to start with: