"Brass from heck": worst case scenario?


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yhtomit
August 3, 2007, 11:50 PM
Something I didn't know until I spotted some threads dealing with it on this forum: Brass that's been through a hot enough fire is no good for re-loading. Now, it's pretty obvious that some fires would certainly be hot enough to cause damage ("hey, it melted to slag -- can I reload it?"), but here's my problem: some brass that I've collected before knowing about this I pulled from trash bins (large steel drums) at a range (really -- not recylcling bins, just trash), and I know that there were fires made in some of the bins. However, from what I've ever seen of the trash cans there pre-fire, and from the amount of ash contained, I know that these fires were small and short lived. However, it worries me just a bit -- I'd sure hate to toss out hundreds of scavenged rounds unless the worry was very well justified! (I've pulled perhaps 50, perhaps as many as hundred, rounds from the trash bins -- but they're mixed in with other cases found on the same days, and I can't distinguish them visibly -- if I had been able to, I would not have collected 'em.)

So:

a1) what's the worst thing that could happen if I reload and fire a cartridge that's been fire-damaged? (And explain your work :) -- that is, don't just say "You'll experience a kaboom, and God will strike you dead" without explaining the reasoning.

a2) How much fire is too much for brass to remain viable? I know that the answer "any is too much" is convenient, but it also seems like a cop-out. I'd like to know a more detailed idea; if a case is in a barrel where a fire was lit which lasted less than a minute and burned only paper, what are the odds that it's affected? I understand that the military runs brass through something like a giant furnace (a popper? As in "to pop those primers like popcorn"?), which I presume runs hotter and longer than a quickie trash-shrinking fire. The popped brass is no good for reloading, I gather from reading on this site, but at what point (temperature and time) does it actually become a problem?

b1) Is there a way to tell (now that at least within certain batches of empty brass, which I know came from the range on a certain day) whether a case has been fire damaged? I tried to toss away (or rather put in my recycling collection for eventual sale as scrap) any that *looked* in any way affected by the heat, or that I found in ashes rather than in relatively pristine looking boxes which were themselves unaffected by fire (I love how neat many shooters are in their disposal :)). Those, I know got added to the trash after the fire was over and done.

b2) Will a fire-damaged case seem any different on the reloading press? Will it not resize correctly, for instance?

I want to be safe, but I also don't want to be wasteful -- Insight appreciated!

timothy

EDIT: I tossed (into my recycle-for-money bin) all the brass that might have contained any of the cases that had been in the fire barrels. Seems a pity, but I was blessed at the range with a few hundred fresh, just-fired brass cases in .45, 9mm and a few other calibers.

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trueblue1776
August 4, 2007, 12:09 AM
what's the worst thing that could happen if I reload and fire a cartridge that's been fire-damaged?

The molecular structure in those case were cold pressed into the shape it is in now, when it was exposed to heat they could have been relieved, kinda like a shorter (weaker) grain, also any factory annealing is most definitely gone. They are most certainly weaker than unheated cases, how weak is for you to decide. I would trash them pronto.

If you have a cheap NEF or something, you can try using them, but there is a chance they would crack while resizing and ruin your dies with some nice scratches. Up to you dude.

the pistolero
August 4, 2007, 06:49 AM
YMMV, and in this case does, but the uncertainty with range pickup brass is precisely the reason I pick up only my own brass from the range to reload. I just don't feel comfortable loading unknown brass. Maybe at some point in the future, but not right now.

Texastbird
August 4, 2007, 10:22 AM
How hot does brass get just from being fired? Or is time a bigger factor? I know its plenty hot when it flips down the neck of my shirt...

Ol` Joe
August 4, 2007, 10:55 AM
Brass is annealed at, I believe about 650 deg F and the grain structure of the cases will start to change at around 470 F.
A burn barrel fire is much hotter then this and will likely take the temper from the brass. Brass that is too soft in the body is a accident waiting to happen, and too hard will cause it to crack rather then expand during fireing, another problem we don`t want.
Don`t use brass from a fire! Ever!

snuffy
August 4, 2007, 02:37 PM
If you're really interested in brass and what heating can do to it, then read this; The annealing process, "softens" the neck of rifle cases. If you heat the WHOLE case too hot, it is junk, it cannot be re-hardened to make it usable for reloading.

http://www.6mmbr.com/annealing.html

yhtomit
August 4, 2007, 05:53 PM
Thanks for the replies -- OK, I'll toss all brass I even suspect is from the fire-barrel. Better safe then sorry, etc.

A serious question, though, from my original post above: is there a way to tell if brass has been harmed by heat? Is there a measure of elasticity / hardness that could be employed (outside a laboratory, of course)?

Perhaps today I'll get lucky with the brass collection at the same range ;)

timothy

HankB
August 4, 2007, 05:59 PM
When brass is formed, it gets harder ("work hardens") which increases the strength of the case. This is a useful property in the area of the case head, as you don't want the brass to flow in that area.

"Most" of the case head is going to be supported by steel - the bolt face, the chamber walls, etc., but some portion of the case head is necessarily going to be unsupported - that has to withstand the full chamber pressure generated when the cartridge is fired.

Most cartridges are designed so the pressure inside the cartridge will put the brass under a compressive stress, but if the brass is weakened by being annealed, it can flow - much like toothpaste in a toothpaste tube - and blow out where it's unsupported. This is generally a bad thing. Annealed brass flows more easily than brass that's in its work-hardened state, so brass that has been through a fire may well be dangerous to use.

Annealing of the case mouth/shoulder area is a different matter, as the stress is almost purely compressive and, unless the pressures are incredibly high, there's no problem.

FieroCDSP
August 4, 2007, 06:53 PM
Yellow brass is at a premium.. Save the cases in a bucket and recycle them for cash, instead of trashing them. Even if no scrap yard will pay you for them (doubtful), turn them in, as any brass that makes it back into the system keeps overall costs down. I've got a few small boxes full, waiting to be made back into green gold.

Master Blaster
August 4, 2007, 07:47 PM
If you have really old or questionable brass, toss it and get some better brass.

Dont load max loads, your more likely to just get a split case.

I mainly load target loads, lots of .45 acp I would not hesitate to load a case 20 times as long as the brass didnt show any sign of bulges or seperation.

If the brass in a batch of brass looks suspect I toss it.

Sunray
August 4, 2007, 10:14 PM
"...hate to toss out..." Like FieroCDSP says, you can take it to a scrap yard and sell it. Mind you, it takes a lot of brass to make it worthwhile.

yhtomit
August 5, 2007, 12:01 AM
Sunray and FieroCDSP: Oh, don't worry -- I meant toss out only into the container for eventual brass recycling :)

Tomorrow I'm likely to buy a case apiece of factory-new brass-cased .45 and 9mm ammo; that, along with the known-good stuff I have gathered and been given, should stand me in very good stead. Just now regret the time spent gathering brass which prudent counsel seems to advise should be tossed as the basis for reloads. If only I'd kept the trash-bin ones in a separate baggie, but I hadn't thought at the time of the problems with it.

timothy

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