Wednesday, February 25, 2009

Praxis: Ammo Corrosion Question



"VERY FEW ROUNDS WILL HAVE SOME SLIGHT TARNISH THAT WILL NOT AFFECT FUNCTION. PURELY COSMETIC AND VERY MINOR." [Caps in the original; I am not yelling.]

"The BS penalty flag is on the field!"


Question from a good friend:

"Received my order of German 7.62x51mm. Serious corrosion problems with 25% of the order. We will see what transpires. . . Note their description (”slight tarnish”) versus the reality of the attached picture. Assuming the badly tarnished and/or corroded rounds pass the chamber-gauge test, do you think the brass will maintain sufficient intregrity to shoot? Since they are Berdan primed, I am not worried about reloading (although I will save the brass for re-sale as scrap)? And I was so looking forward to having a bunch of German 7.62.


Now I'm not going to make a big deal about the ethics involved here until my buddy hears back from the distributor involved. However, he asks a good question about when is "corroded" too much? Opinions?

10 comments:

thedweeze said...

Coupla months ago, I bought some 8mm Mauser ammo with a 1939 headstamp. There were a few black splotches, but nothing like the picture.

I'd send it back.
And, I'd like to know who the guilty party is. My wallet votes too.

oldfart said...

I once bought a bunch of Turkish 8X57 that made that made his 7.62X51 look good. Most of it shot just fine and I could probably have shot it all but I was too chicken to try it.

A bit of steel-wool while watching TV will weed out those few rounds that might be corroded through.

AlanDP said...

I tried to ask this very question on my blog some time ago, and I all I got were snarky replies like, "If you're afraid to shoot it, send it to me."

I was loathe to use some corroded ammo because any spot that has corrosion means that spot also has LESS BRASS, therefore, it obviously could be dangerous to shoot.

So if you get some real, valid info on this, please post it.

Anonymous said...

discoloration is one thing, enough corrosion to copmpromise the integrity of the shell is another.

No way I would shoot 7.62 X 51 that looked like that!

tom said...

Not knowing the terms of your sale, I got gifted some .30-30 antique win that looked like that a number of years ago from somebody's heirs that had been "in the garage for years".

Application of a wire brush and some steel wool and I plinked with it without a misfire in an old bolt .30-30, which was well cleaned after, but I wouldn't have depended on it doing so. Ended up being decent reloadable brass or else I likely wouldn't have bothered.

Vanderboegh said...

Anonymous:

Good guess, but we're not going public with it until they've had a chance to make it right.

Anonymous said...

It appears that this is de-linked ammunition, as the corroded locations appear to be in the same area, where MG links links attach to the round.

It's a judgment call and perhaps some plain ol' common sense.

it appears that you bought these from Eric at ammoman.com, give him a call tell him your concern. Eric, is an upstanding guy.

http://www.ammoman.com/webstore_308.htm

http://www.ammoman.com/images4/308-GERMNATO147-CAN2.jpg

308 / 7.62X51 GERMAN NATO AMMO 147 GRAIN
FMJBT NATO BALL
NATO HEADSTAMP
1990's PRODUCTION
100% NON-CORROSIVE

VERY FEW ROUNDS WILL HAVE SOME SLIGHT TARNISH THAT WILL NOT AFFECT FUNCTION.
PURELY COSMETIC AND VERY MINOR

DAG MANUFACTURE AND THOSE OF YOU THAT KNOW THIS AMMO WILL AGREE. IT'S FANTASTIC !

BRASS CASED - BERDAN PRIMED - LEAD CORE

500 ROUNDS PER USGI AMMO CAN
LOOK AT THE POSTED PICS

tom said...

Corrosion is sorta like blood, it doesn't take much for it to look like a WHOLE LOT. KEEP IN MIND, a significant portion of that corrosion came from the ENVIRONMENT the ammo was stored in, not the actual cartridge cases.

If you want to know what the actual brass thickness is, it's really simple.

A: Pull a bullet from one of the worst of the lot after you've steel wooled it.

B: Using a saw to "adapt" the case as needed, depending on where the corrosion you wish to measure is as related to remaining metal strength, put a mic on it and measure.

Interestingly enough, you can do this with high end factory new brass and get mic readings all over the place.

Then you can move to hardness testing and see where it lands on that scale.

Or you could just clean it up and shoot it and take your chances. I've done all of the above.

Without measuring, you're just guessing, EVEN WHEN you use pristine looking commercial or mil ammo. Keep that in mind.

If they'd polished it up before mailing it to you you likely wouldn't even suspect a thing.

There's a reason humans invented measuring tools.

TJP said...

I wouldn't touch anything but the leftmost row. I'm still destroying dozens of shotgun shells that corroded in the basement of my last home. The stuff looks like it's on the surface but it goes through.

Considering the chamber pressure of a .308 Win, I wouldn't mess with anything where the head or the web had been compromised. That's conceptually similar to annealing the wrong part of a case, though the corroded ammo would fail for different reasons.

All is not lost. The bullets are worth saving. The powder may still be good in the cases where the corrosion hasn't gone all the way through.

And what's this about single-use Berdan-primed cases? Get a primer hook to de-cap them, and then drill out the anvil.

Uncle Lar said...

The function of the cartridge case, other than to hold the rest of the components together, is to seal the chamber so that the propulsive gasses are directed out the barrel. As long as the corrosion does not weaken the brass to the point it fails and you get gas blowback through the action the cartridge has done its job. The other issue with corrosion like what's shown is that if left in place it might cause sticky extraction of the empty case, so some cleaning and polishing is in order. Based on research I did a while back you can run loaded rounds through a case tumbler to clean them up.
Still and all, I'd have to say they were not as advertised, so you do have a legitimate issue with the vendor.