Do Old Cast Bullets Get Brittle?

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  • tomcat13

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    Feb 16, 2010
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    Does anyone know if Cast bullets get Brittle as they get Old(15+ years old)? Went to the Range today & shot some Old .45acp Reloads I inherited from a 97-yrs old Uncle that recently passed. The loads were probably at least 15 years old & Not "Hot." One of the Cast Bullets broke off, even with the end of the Case (While in the magazine) leaving part of the bullet still in the case & part in the bore. I stopped shooting those rounds at that point & that part of the bullet in the bore was easily removed. Don't know if I should just chuck the rest of the batch (aprox 200 rounds). Pretty sure the Cast bullet recipe was Lead & Antimony.
     

    Leadeye

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    Jan 19, 2009
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    I've cast and shot cast for 40 years, never have had one break like that. Antimony will pick up hardness in lead alloys and I've increased that even further by dropping in cold water, but I've never had them break.
     

    throttletony

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    Jul 11, 2011
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    To my knowledge, lead (and cast bullets composed primarily of lead) do not get brittle over time. I would guess that wjatever else is in the mix is creating the brittleness... and I'd bet they were that brittle the day they were cast.

    IANAL, this is just my initial impression, i have no chemistry degrees on which I base this opinion... but I did stay at a Holliday Inn one time.
     

    oldpink

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    I'm not a caster, but I'll have to agree that the bullets as dropped were brittle from the very beginning, possibly as a result of an alloy problem, or possibly as a result of some other problem with the casting process, be it temperature, voids in the mold, impurities, or some other fault.
    My dad has some ancient .32 Rimfire ammo with pure lead bullets, and none of it has broken, even though this particular ammo is well beyond 50 years old.
     

    Thor

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    Could be anywhere
    This could have been an issue with a single casting where some impurity got into the mix and created a single bullet with a weak sedentary line.

    Of course this is all conjecture from 20k'.
     

    Leo

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    It was not age, it was a problem in the alloy. Protected from the environment, the decay into lead oxide is far longer than we will live to tell.
     

    Leadeye

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    I've got some high antimony alloy I use, so hard it rings when you drop it. Tried hitting it with a hammer, no cracking.
     

    mssmith44

    Marksman
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    Dec 21, 2011
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    I have seen the very same problem with cast bullets.
    They were made by someone else.
    In looking at the break it seemed to be crystallized.
    I think too much antimony, too hot a casting pot and dropping into water.
    This is all a guess of course without a detailed metallurgical study.
     

    NKBJ

    at the ark
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    Apr 21, 2010
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    tomcat,
    Alloying elements can do some squirrelly stuff to lead allots.
    A stress line set up over long periods of time can propagate in various metals, it's just more unusual in lead alloys.
    If I had to take a shot at what caused the fracture you experienced it would be that the alloy temperature when it left the mold was inbtween the start and the finishing of solidification. The branching structures within a lead alloy casting can be in the process of forming and the casting can hold it's shape but still be weak because the constituent parts of the mix with a lower melting point are still liquid.
    Check out this lead alloy ingot that was dumped out of the pan before sufficient solidification had taken place. That's how you get a crack in something as malleable as a lead alloy.
    mystery metal.jpg
     

    noylj

    Marksman
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    May 8, 2011
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    Mine never did, but the cheap Crayola wax lube will get brittle--but, in the bullet is loaded, it isn't an issue.
     
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