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porthos
10-23-2020, 07:14 PM
started casting 9mm bullets out of what i call "mystery mix". i mixed this stuff many years ago out of some unknown stuff. at that time the bhn measured 11. now it is a few points higher.?? it was analyzed by BNE on this site. the analysis is 92.4% lead, 5.8% antimony and 1.9% tin. seems a lot of antimony to have measured 11 bhn many years ago. how long should i wait before i check the hardness of fresh cast bullets. my hardness tester is a LBT.
kevin c
10-23-2020, 07:40 PM
Your analysis is just fractionally under the Sb and Sn content of hardball, which is about 16 BHN according to my resources (lasc.com). The same articles mention hardening over time, with the lowest numbers found right after casting and increased hardness in the next week or so, and some slight softening over months.

Did you average multiple tests as I recall being recommended for the LBT (I have the same), and when were those first measurements done? What is the average now?
porthos
10-24-2020, 11:45 AM
alloy was poured into ingots in may 1991. at that time or shortly thereafter bhn was measured at 11. same ingot today measures14-15. bullets cast yesterday measure 13. hope they work well in 9mm at 1000fps
kevin c
10-25-2020, 03:59 AM
I use a 95-3-2 or 96-3-1 alloy, sort of a 1:1 hardball:soft mix plus a bit more tin in the first case, to cast 9mm that I HiTek coat and shoot without problems at 900 to 925 fps. At just a bit more velocity, I think your harder alloy should do fine, assuming good fit and adequate lube or coating.
PBaholic
10-30-2020, 03:42 AM
how long should i wait before i check the hardness of fresh cast bullets.

After 48 hours you'll get a good idea what the hardness will be. Your hardness will continue to increase over time, and will likely even drop after a month or two.
fredj338
10-30-2020, 02:16 PM
alloy was poured into ingots in may 1991. at that time or shortly thereafter bhn was measured at 11. same ingot today measures14-15. bullets cast yesterday measure 13. hope they work well in 9mm at 1000fps

Should be fine. I run range scrap in my 9mm, coated, 10-11bhn, works fine.
white eagle
10-30-2020, 03:29 PM
how long?
wait a couple of weeks for the bhn to settle in
when using alloy with antimony