doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Lead alloy formula?

It is an original 1880s paper patched lead bullet that I am guessing was swaged and not cast. Probably missing the void that my wonderful cast bullets have

Care to share your spreadsheet, Brent? I am 99% confident the 1880s bullet is lead and tin only, and does not contain antimony or mercury. Thank you very much

50/50 ratio by volume

Pure Pb bullet is 1.59cm3, unknown bullet is same volume

50% Pb by volume in unknown mix is .795cm3 x 175.03gr/cm3 = 139.14gr
50% Sn by volume in unknown mix is .795cm3 x 112.12gr/cm3 = 89.13gr

Pb + Sn = 228.27gr for approx same volume bullet

pamtnman,
I'd be happy to send you a copy. I just need your email. I do not see one listed for you.

However, it will not exactly fit your specific needs. It was made for casting bullets and moving between different Pb/Sn alloys. Volume is not a fixed variable, which is what you are looking for. I could pencil it out for you however. These are two identically shaped bullets, right? From the same swage die or mould?

Losing 50 grs from a 278 gr bullet by just adding tin to the mix - seems like a lot. May not be possible.

I'll sharpen my pencil in a minute. Gotta feed ponies first.

I appreciate it, Brent. Hi to the ponies. When i was a kid we had a pony in a corral next to the house.

Well, it's is doable.

I pencil it out to be a 1.52 to 1; lead to tin ratio. That's a heck of a lot tin! What we consider to be hard bullets is 16:1 alloy and some folk will go as hard as 12:1. No one goes even close to 1.5:1.

Bullet hardness is what matters, not weight. Hardness increases with a decreasing ratio of Lead:Tin. However, it is a diminishing relationship such that little if any hardness is gained once you cross something like 12:1. If you want harder, you jump to antimony or something else (copper, silver, ...?). Tin is also very expensive relative to Lead. So that makes me think that something else is an issue here. I doubt that bullet is really 1.5:1 lead/tin and nothing else, but it is possible.

Well thank you for contributing to this, Brent. I think you were interested in the old historic paper patched bullet I pulled a couple months ago. It weighs the proper 228 grains (450-400 BPE), and Mike Rowe had said he expected it to be a 12:1 alloy. Well, I had an adjustable mold made, and the same length pure lead bullets come out at 278 grains, so I suspect like you that something else is at play. One thing I noticed when i went back and looked is the original bullet has the copper peg in the tip, which must displace 5-10 grains of lead weight. So the actual poured pure lead bullet is heavier than the original because of the solid nose. Still, if the original was 240 grains with the solid nose, we still have a disparity of 38 grains, which is hard to achieve with just tin alone.

Check your math.

What do you come up with?

Clap, please lead us forward on this. my experience with math is it is taught by people who love math to people who either love math or who are interested in it enough to pay attention and try to learn it. the other 95% of the human population remains fully functional day to day without math, beyond a few basic calculations here and there. math is taught in ways that are impractical for daily use, so that even people who could be interested are driven from it like wildebeests wildly fleeing a mob of hungry lions. thus are requests for help with what may be basic math born
Sincerely and with appreciation,
-scared wildebeest