Expanding cast bullets

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fixit
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Expanding cast bullets

Post by fixit »

I know that this has been hashed out in some degree in the past, but I don't know where, or to what degree, so I thought I'd ask here. What success, if any, could be had with a softer alloy, or perhaps even pure lead subsonic bullet? I figure, with a for purpose design and powder coating, it might be possible to take advantage of the malleable qualities of lead. Granted, this might not be workable in an AR, but for singles and bolts, maybe it could be the bee's knees.
blaster
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Re: Expanding cast bullets

Post by blaster »

I'm not a bullet caster but I have thought about something similar before. like pouring soft lead in the tip of the mold and then pouring a hard alloy for the base of the bullet. I don't know if its feasible but it looks like it might work. maybe someone with casting experience will chime in. 8) as far as powder coating the finished product, I don't think the powder coating would keep the soft lead from mushrooming.
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bangbangping
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Re: Expanding cast bullets

Post by bangbangping »

My experience is that without a substantial hollow point you'll have very limited expansion, even with soft lead. I'm speaking of subsonic.
BJK
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Re: Expanding cast bullets

Post by BJK »

blaster wrote: Thu Oct 29, 2020 4:33 pm I'm not a bullet caster but I have thought about something similar before. like pouring soft lead in the tip of the mold and then pouring a hard alloy for the base of the bullet. I don't know if its feasible but it looks like it might work. maybe someone with casting experience will chime in. 8) as far as powder coating the finished product, I don't think the powder coating would keep the soft lead from mushrooming.
I can't remember who made them but maybe 50 years ago a manufacturer made a bullet in 2 parts. It wasn't poured as you suggest, but instead the front portion was made using soft lead and the read section was made in hard lead and joined together. I don't remember how they were connected.

Edit: Ummm, that should read "rear section" and not "read section".
Last edited by BJK on Sun Nov 01, 2020 9:41 am, edited 1 time in total.
popper
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Re: Expanding cast bullets

Post by popper »

BruceB soft point method. Pour soft in the nose and follow with harder. Works fine. HP & AR don't always work together. Cup point and soft or BB initiator work OK. Most of the heavies have SP so you'd lose a lot of weight making HP. I just use FP and 50/50.
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gds
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Re: Expanding cast bullets

Post by gds »

BJK wrote: Thu Oct 29, 2020 5:58 pm
blaster wrote: Thu Oct 29, 2020 4:33 pm I'm not a bullet caster but I have thought about something similar before. like pouring soft lead in the tip of the mold and then pouring a hard alloy for the base of the bullet. I don't know if its feasible but it looks like it might work. maybe someone with casting experience will chime in. 8) as far as powder coating the finished product, I don't think the powder coating would keep the soft lead from mushrooming.
I can't remember who made them but maybe 50 years ago a manufacturer made a bullet in 2 parts. It wasn't poured as you suggest, but instead the front portion was made using soft lead and the read section was made in hard lead and joined together. I don't remember how they were connected.
I tried that technique. Made some beautiful bullets. But at subsonic velocities zero expansion.
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Re: Expanding cast bullets

Post by popper »

Takes about 20% tin.
cdl
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Re: Expanding cast bullets

Post by cdl »

I've used up the last of my life long free "mystery lead" last month.

No way to know what it was, so I never worried. Granted, the only cast bullets I ever got to expand were shot at steel. They looked just like coins there on the ground...

Now that I'm buying my lead, I'm just starting to pay attention though.

I had a doctor friend tell me not to practice medicine once, but here we go anyway...  

It seems brittle hollow points explode where malleable hollow points expand and the really hard ones just tumble around.

We only need 2% tin for our alloy to flow and fill but the alloy of old I read about for hollow points is 16 to 1, 5.88% tin, Brinell of 11. More tin harder, less tin softer. Depended on velocity and tip design. Under 1000fps we'd probably use less tin in the old days.

These days Tin is expensive and everything seems to have Antimony in it. Antimony makes bullets harder, then brittle. Brittle is cool when blowing up water jugs, not so much for penetration.

So, what is it about Antimony that makes bullets brittle? My simplistic understanding is that the amount in excess to what the tin can absorb and the lead can absorb, forms a hard brittle matrix within the alloy as it cools. Remember I was told not to practice medicine.

So, how do we get our Antimony under control and not spend 10x for tin? Remember we really only need 2% tin to get the mold to fill. Well we need to know that absorption rate and keep our Antimony below it. Apparently Tin is 50:50 so 2% Tin can suck up 2% Antimony and lead is 1.5% so all the lead can suck up about 1.5% of the Antimony. That means if we keep our Antimony under 3% with 2% tin we should be a malleable Brinell of 12. Then 2% Antimony with 2% tin and there we are, Brinell of 11, same as 16 to 1 of old, but almost a third of the tin and we dealt with the pesky Antimony.

Course I'm still working on this, so any first hand experience is welcome. Don't you just hate it when you get the end of a long post and the person says; "This is what I think, but I don't really know..."
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