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I might have bought some bad 10mm Kurtz brass...

Discussion in '10mm Reloading Forum' started by Meathead9, Aug 9, 2012.


  1. Meathead9

    Meathead9
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    I bought 5k pcs of 40 brass a few months ago (LE range pickups from a retired LEO), and I just now got around to really checking them out. I know, that was dumb. I'd say atleast 75% look like this, and these cases spent 6hrs in my vibratory tumbler (walnut/nufinish).*

    Would you reload these? Will the tarnish/corrosion cause weak spots in the brass? I don't care about how pretty they are or aren't, I'm just not big on case failures. They were supposed to be for my USPSA 40 Major Load, so pretty high pressure stuff.
    There aren't any cracks, splits or bulges, and they looked pretty much the same before going into the tumbler.

    [​IMG]

    [​IMG]
     

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  2. dm1906

    dm1906
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    6 hours in walnut is bad enough. If they looked like that after any cleaning, I wouldn't use them. The "tarnish" isn't just corrosion, but often is an indicator of a poor alloy. Those are about as bad as I've seen, in bulk. I see some like that, about one or two in a couple hundred, but 75% is reason to not use any of the lot (of the same headstamp), especially for full pressure match rounds. Bottom line - don't use them.
     

    #2 dm1906, Aug 9, 2012
    Last edited: Aug 9, 2012
  3. Meathead9

    Meathead9
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    Thanks dm, I was afraid of that. It's not worth constantly having to worry about blowing up my gun, so off to the scrapper they go... Maybe the guy will give me a refund
     
  4. Yondering

    Yondering
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    I'm not sure where you got that information, but it's misleading in this context, at the least.

    That almost certainly is corrosion, from sitting outside in the dirt and rain for a couple years... The "tarnish" is where the corrosion was partly rubbed off in the tumbler. Corrosion like this can and does cause a change in the alloy, but it's not caused by poor alloy.

    I see a lot of range brass that looks like this. I have a bunch of .40 brass like this; it's a pain to sort through. I've found that it's mostly OK to use with plinking loads (I use 180gr cast over 4gr Bullseye), but the corroded brass does sometimes get brittle, and isn't safe for moderate to full power loads. Problem is, you can't tell if it's brittle or not, until you use it, so I cull all of the brass that looks like that.

    You can get the corrosion out with an ultrasonic cleaner and brass cleaning solution, but in the badly corroded spots you'll notice the brass changed to a copper color. The brass is weaker in those areas.

    Bummer, you got hosed.
     
  5. dm1906

    dm1906
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    It is, in fact, exactly what it is. Poor alloy. The "blue" corrosion areas are areas of "more copper and less zinc", which cause the patchy areas. This is very poor alloy. Many lots of brass have this characteristic, some more than others, but most are not as prominent. This lot, after a LOT of polishing, and very abrasive at that (the walnut), indicates it is deeper than just mild surface oxidation. That's a LOT of blue, with a very definitive hard line to gold. Very poor alloy. Period. "Cleaning up" this brass is asking for trouble, as you will only be masking the true composition. I'd rather be lucky than good, but that option is rarely available to me.
     
    #5 dm1906, Aug 9, 2012
    Last edited: Aug 9, 2012
  6. _The_Shadow

    _The_Shadow
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    They do look pretty nasty! Over the long term the brass will probably crack or split because of change in the brass. Brittleness

    Be careful of your dies! They can be scratched on the interior or fouled with the gunk!
     
    #6 _The_Shadow, Aug 9, 2012
    Last edited: Aug 9, 2012
  7. Yondering

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    The end result is a poor alloy, but the corrosion causes the change in alloy, not the other way around. Any brass will corrode and show blue oxidation when exposed to the right conditions, for enough time.

    I do agree that the brass is scrap.
     
    #7 Yondering, Aug 9, 2012
    Last edited: Aug 9, 2012
  8. dwhite53

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    #8 dwhite53, Aug 10, 2012
    Last edited: Aug 10, 2012
  9. _The_Shadow

    _The_Shadow
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    One other thing comes to mind...ammonia is very caustic and corrosive to brass metals. Some cleaners and polishing agents contain ammonia...Big No No for brass casings!
     
  10. Yondering

    Yondering
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  11. glockout

    glockout
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    I sometimes have reloaded dark brass. Usually in 9mm. When I inspect the brass many of the dark ones are cracked either when I pick it back up or when size it.
     
  12. JimIsland

    JimIsland
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    Yuk.....I'd be pissed.
     
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