Ratio of shot to lead to harden boolits

[ghh3rd]

My stash of lead is about BHN 12. I'll be casting boolits for a .357 that I have on order and want harder boolits. I read that shot contains about 1.5% arsenic, and that arsenic helps harden water cooled boolits.

Is there a 'rule of thumb' on the ratio of shot to lead alloy?

Thanks

Randy

[jsizemore]

Arsenic speeds up the hardening process. It doesn't make them harder.

[upnorthwis]

Unless you're trying to drive them thru steel, 12 BHN should work just fine. So why is it you want them harder?

[ghh3rd]

I've just always felt like I was just squeezing by at 12 BHN + water cool when I cast for my .44 mag, and thought I'd up it a little bit. I could just try it and see I suppose, but suppose one has a good reason to want a harder boolit ... I wonder how much shot would be the 'norm'?

[woody1]

Chances are your alloy already has "some" (prob'ly enough) arsenic in it as it occurs naturally with lead and isn't smelted out. Search the forum for "arsenic" and you will get lots of info, some good, some? Bottom line is a tablespoon or two of hard shot will add arsenic enough as it takes very little.

[rosewood]

I read that back when Elmer Keith was using "hard cast" lead for his heavy loads, that meant harder than pure lead and he was using something in the 12 BHN range.

[jmort]

You would have to calculate, but Magnum shot is around 4 to 5% antimony
Chilled shot is 2%, so that will not help much even with the arsenic content.

[JonB_in_Glencoe]

I'd start by heat treating your "stash" alloy, before I'd spend money on shot.
http://www.lasc.us/HeatTreat.htm

[gundownunder]

I use clip on ww with 2% tin added. If I'm not mistaken, that would be about 12 - 13 brinell.
I've driven thousands of them through my Marlin 357 at up to 1750 fps and never got any leading.
I shoot hundreds of rounds before I even bother cleaning the barrel.
If your bullet is fat enough, and your lube is good enough, your 12 brinell should be good enough.

[243winxb]

Alloy need 2% antimony to oven heat treat, water cool. See Lymans FAQ on website.

[MT Gianni]

If you want harder lead go through Rotometals, a sponsor with an ad on the top banner and get enrichment metal.