Bismuth and lead free casting?

[Sandspider500]

Had some old zinc boolits I had cast years ago. A lee 255 that weighs 155gr and a ranchdog 290 that weighs 180gr. Each took significantly more hammer blows before they cracked. The smaller lee did expand. The larger one acted like a nail into the hard lead ingot.




Zinc also looks very similar when broken apart

And here a broken apart zinc wheel weight.


I had tried to mix zinc with bismuth before and thought I had done it. But the zinc was just floating on top of the bismuth like oil on water. I had a 10lb pot about 2/3 full with 1/3 of that being zinc. I cast with it and then something changed. The last boolits were some kind of mutants with weights that were all over the place.

Here's the mutant zinc bismuth boolit.

It weighs 200gr.



The zinc boolits came out to 180gr

What is this stuff? Zincsmuth

[Sandspider500]

The last 2 are very close to what the rotomeatals lead free bismuth alloy should weigh.

[Delkal]

Tin does alloy with zinc and I wonder if it would make the zinc alloy less brittle.

Has anyone tried pewter? It is closer to the density of lead and should be malleable. Pewter is relatively hard but cutting it with more tin could soften it. While casting with tin / pewter used to sound crazy due to cost it would still be a lot cheaper than the $30 a pound bismuth alloys. Or lead free solder?

[Sandspider500]

The brick of pure bismuth I have cost 7 or 8 a pound i think.

[Sandspider500]

I found 2 that weighed almost exactly the same, 200grs. I cut 1 in half with a Dremel, I dunno why.



As I'm cutting it, some small beads form and it starts to sweat out some metal.


I broke one of the half's with a hammer.

I continued to beat the piece and it flattened out a bit and embedded itself in the lead.


The bad thing about bismuth is it's brittle, the bad thing about zinc is it's too light. If bismuth can be mixed with zinc and get somewhere the density of copper....

One of the mutants did weigh 213gr, if it can be mixed to get to 220gr, I'd be happy with that. It would be 40gr more than zinc, and it seems to be almost as tough as zinc.

[Bigslug]

It's been several years - my Dad tinkered with the Rotometals alloy by progressively increasing the tin content. . .which unfortunately decreases the projectile weight.

We went from a bullet that tended to shatter on water jugs to one that held together, but as I recall, did not expand appreciably.

Ultimately, we decided that hunting our area was hard enough as it is without complicating things further with using old, iron-sighted museum pieces. We opted to practice with lead and hunt with Barnes TTSX's. By the time you consider licenses, tags, gas, lodgings, camp food, etc..., the price of your projectiles is the least of your worries.

[dverna]

It's been several years - my Dad tinkered with the Rotometals alloy by progressively increasing the tin content. . .which unfortunately decreases the projectile weight.

We went from a bullet that tended to shatter on water jugs to one that held together, but as I recall, did not expand appreciably.

Ultimately, we decided that hunting our area was hard enough as it is without complicating things further with using old, iron-sighted museum pieces. We opted to practice with lead and hunt with Barnes TTSX's. By the time you consider licenses, tags, gas, lodgings, camp food, etc..., the price of your projectiles is the least of your worries.

You are so right. There is no practical upside to using cast bullets for hunting with a modern HV rifle. If they banned lead bullets for hunting, I would use copper bullets.

And if there is a widespread ban on lead hunting bullets, the cost of copper bullets will come down.

Lead will not be banned for target shooting/plinking. At least not in my lifetime. Even CA allows lead for target shooting.

[Sandspider500]

That's the spirit.

[Bigslug]

Well Keptin, ye kinna change theh laws of physics (or molecular chemistry). I'm not knocking the science; just pointing out its challenges.

We never did get around to trying hollow points, but given the inherent brittleness of bismuth, you're likely looking at a frangible nose until you reduce the bismuth percentage by making it a mostly tin bullet, and at that point, your mass is reduced to where you may not want expansion slowing it down and reducing penetration anyway. Frangible may be good or bad, depending on the task.

We concluded it was going to end up being a solid with big meplat at high velocity (compared to the same shape in lead) affair. That would give adequate penetration and hopefully adequate tissue damage. The range would get reduced because of the crappy aerodynamics of a school bus-shaped bullet paired with the reduction in momentum. We were guesstimating .30-30-like trajectories.

We mainly wandered this road in the hopes of hunting with an old Ballard .45-70 and a Marlin .38-55 with odd dimensioned bores in our lead-free state, but the realities of our low-success-rate zone steered us back to modern cartridges pushing Barnes at speeds that allow for point blank trajectories to about 300 yards - and they kill deer very well.

I dunno. . .for shorter ranges with blunt handgun bullets that I'd not be expecting much of a trajectory out of anyway, there's probably something to be explored, but if you're going to hunt with a bottlenecked cartridge and optics, I have to give expanding coppers the nod. They manage to crack the ductility problem with a nose that expands to about 1.5 starting diameters and holds together at high impact speeds, and they solve the penetration problem by giving that expansion in the form of a four-petal cross-section that gives that diameter without drastically increasing frontal resistance (think archery broadhead).

If you can achieve those attributes with non-lead alloys from a hand-poured mold, believe me, I'm all ears.

[Plinkmeister]

That's the spirit.

That is absolutely too cool!