BHN For 16-1 lead alloy

[Rain2436]

Anyone know what the above BHN is. I purchased alloy from Roto Metals at 16-1. I casted some and tested it for hardness. I t returned an 8.7. This I know is way to soft for the alloy I purchased. It is even stamped 16-1. Any help!

[Hickory]

What were you planning to use it for?

[Outpost75]

Anyone know what the above BHN is. I purchased alloy from Roto Metals at 16-1. I casted some and tested it for hardness. I t returned an 8.7. This I know is way to soft for the alloy I purchased. It is even stamped 16-1. Any help!


1:16 should be 10-11 BHN.
Which hardness tester are you using, and how and when was it last calibrated?
How many days after casting are you taking your measurement?
What are you using as a hardness standard for comparison?

[Cosmic_Charlie]

I just ordered 40# of it for Lee's tumble lube 158 tc mold. Was planning on loads at 1000 fps. with AA #7. Not a huge problem to make it a bit harder I suppose with some lino.

[quail4jake]

That sounds like a great alloy to mix with linotype or some other antimony source and Pb to make use of the Sn in it. My 20:1 made from pure Pb and pure Sn reliably comes in at BHN 8 using a SAECO tester calibrated to Pb BHN 5 and Linotype BHN 22. What I'm saying is that I think this is reliable, so 16:1 at under BHN 9 sounds right. 6.25% Sn is rich, expensive and more than necessary for castability. If your goal is BHN 10 you may want to try making an alloy with 97% Pb/1% Sb/2% Sn, I use that for some handgun boolits, BHN 8 as cast and BHN 10 in 4 days. When you measure hardness of Pb/Sn alloys compare as cast and a week later, they age soften more so in the higher Sn alloys.

[brewer12345]

That sounds like a great alloy to mix with linotype or some other antimony source and Pb to make use of the Sn in it. My 20:1 made from pure Pb and pure Sn reliably comes in at BHN 8 using a SAECO tester calibrated to Pb BHN 5 and Linotype BHN 22. What I'm saying is that I think this is reliable, so 16:1 at under BHN 9 sounds right. 6.25% Sn is rich, expensive and more than necessary for castability. If your goal is BHN 10 you may want to try making an alloy with 97% Pb/1% Sb/2% Sn, I use that for some handgun boolits, BHN 8 as cast and BHN 10 in 4 days. When you measure hardness of Pb/Sn alloys compare as cast and a week later, they age soften more so in the higher Sn alloys.

I cast some boolits today destined for 38 special loads (and likely not hot ones at that) and wanted to shoot for BHN 10 to 11. I used range scrap with 2 to 3% pewter added to the pot. This looks on paper like it will be 1% Sb and 2 to 3% Sn, which should be right at what you were suggesting. Is this an alloy I should expect to soften over time, or is the modest level of tin in the mix too low for that?

[Larry Gibson]

Rain2436

Given the "8.7" BHN figure I'll assume you're using a Lee BHN tester(?). I also use the Lee tester but have it mounted in a microscope so very accurate measurements are possible. I also have used certified pure lead and linotype and then using the measurement from those "calibrated" the conversion scale. I use quite a bit of 16-1 alloy and find the BHN runs 9 - 10 after the bullets have "aged" 7 - 10 days. Measuring the BHN of cooled bullets before they harden ("age") always results in a BHN measurement 1 - 3 lower.

[quail4jake]

That may do neither. I make a 97/1/2 alloy that comes up BHN 10 and casts at 10. The trouble with alloys containing less Sb than Sn is that the SbSn system has not formed which can make hardness variable, I've never had a problem with that but I wonder if the age/hardness curve can be unpredictable...

I cast some boolits today destined for 38 special loads (and likely not hot ones at that) and wanted to shoot for BHN 10 to 11. I used range scrap with 2 to 3% pewter added to the pot. This looks on paper like it will be 1% Sb and 2 to 3% Sn, which should be right at what you were suggesting. Is this an alloy I should expect to soften over time, or is the modest level of tin in the mix too low for that?

[Bent Ramrod]

I use SAECO and LBT hardness testers. I generally check a culled boolit or two out of each batch, and don’t bother with the filing of flat portions on the lead that LBT recommends. These are generally sorted for weight within a couple days of casting. Typically, my 16:1 alloy is in the 8.5-11 BHN range.

I use this alloy for paper patch boolits out to 600 yards or so. I’ve never seen any difference in accuracy between the castings at the bottom and the top of the range, although significant losses in accuracy occur with castings that are out of this zone, either harder or softer.

I’ve used range scrap that casts in the same BHN zone with the same results. It also works fine with rifle or pistol smokeless loadings, but I don’t try to exceed 1500 FPS with any of these.