Corrosive Ammo

T

tatters

New member
I tried to test for the corrosiveness of some ammo I bought a while back at a gun show. I need some input.
I pulled the bullets and dumped the powder. I took a piece of bare steel and fired the
"blanks" as it were at the steel. They left burn marks or residue on the steel.
Now all I do is wait, right?
How long till I see results?
This ammo happens to be 7.62x25 from a CZ-52.
The headstamps are 947 93 on the copper looking case (Chinese) and 18 53 32 on the brass case (Polish?)
I saw some info on Makarov.com, but the Polish headstamps listed on their website were not exactly the same as mine.
Not a big deal, but just wondering.


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"Any world that I'm welcome to.....Is better than the one I come from"
 
I think it was Jim Keenan who gave the best explanation of the whole "corrosive primer" deal.

As I recall, cartridges with primers using a mercury compound, when stored for a long time, had some interaction between the mercury and the brass, leading to embrittlement and thus failure of the case upon firing.

Certain types of gunpowder, or a combination of primer and powder, leave a residue in the barrel which is very hygroscopic. The residue would thus attract moisture from the air, and the resulting chemical reaction would etch or rust the steel. In the "old days", then, the procedure was to use soap and water to wash out the barrel, dry thoroughly and then oil it. (With the bolt out, rest the muzzle in a can with hot water and some soap. Use the cleaning rod and a tight patch to act as a vacuum pump to suck the fluid up the barrel. They didn't have semi-autos in the military, then.)

FWIW, Art
 
I use denatured alcohol to wipe down my blackpowder guns. Place a patch on a jag and soak the patch with denatured alcohol. Push it through the barrel. One swipe generally does it for me (with respects to wiping down between shots) but using a fresh patch each time, you can do it several times. It removes the salt and becaused it's alcohol, evaporates quickly; thereby precluding rust. Don't use rubbing alcohol as the water content is higher. You can pick up denatured alcohol at Home Depot or at a paint store.
 
If the ammo is corosive, it will not take long for the metal to rust. The primer is the corrosive part of the round and will not or should not affect the case until fired. That is when the mercury is released. Back when the .45ACP military ammo was corrosive (like in '17) the boxes had instruction that requested the fired cases be placed in containers of water.

The mercuric pirmer compounds also reacted with the powder residue in the barrel to attract water and cause rust to form.

Most of today's bore solvents do nothing for removing traces of mecuric primer compounds from the bore, hot soapy water does a good job then clean with what ever solvent you use.

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Ne Conjuge Nobiscum
"If there be treachery, let there be jehad!"
 
Uncle!

OK, hot soapy water is cheaper than denatured alcohol. You also don't have to make a special trip outside of the house to get it.
 
Here's the text of a message I posted back in June regarding the subject of corrosive/mercuric primers.

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Sorry, but mercuric priming is an ENTIRELY different critter from corrosive priming.

Corrosive primers use a compound called potassium chlorate as part of the priming mixture.

When the primer detonates, the chemical reaction changes this compound to potassium chloride (PC). This is not a problem for your gun prior to shooting the round, only afterwards.

Like its sodium chloride (table salt) cousin, PC is hygroscopic, meaning that it draws water to itself out of the air. (Think of it in terms of black powder residue, same rusting potential.)

If the PC is not removed, it will cause rusting.

The only way to remove it is with water. PC is not soluble in oil. The old GI bore cleaner contained quite a bit of water, just for this purpose. As with a black powder gun you can use boiling water and dishwashing detergent. It doesn't really matter how you introduce the water, you just need to use quite a bit of it to make sure that you don't miss any. Even a tiny speck of PC can cause rusting problems.

Corrosive priming started to disappear from US ammo starting in the 1920s (Remington Staynless and, I think Western Klenshot), but stayed with the military through WW II and perhaps a little after in some calibers.

Commercially, corrosive priming was still used right up through the 1970s on some match ammo, including the old paper-box Eley Tenex .22 Match ammo. I know several match shooters from Camp Perry who still try to find enough of the old ammo to see them through the big matches every year.

Primers containing fulminate of mercury (which also contained PC) are problematic in another way -- on firing, the mercury is driven into the cartridge brass, which weakens it.

This wasn't really known until military powder was switched from black to smokeless, apparently the lower pressure of the BP rounds, along with the powder fouling, meant that the cases weren't badly affected. The US Army took cases fired in training and sent them back to be reloaded. When the Army switched to the smokeless powder .30-40 cartridge, they began getting a LOT of case failures on the second firing, which was eventually tracked down to the mercury in the primers.

After about 1895 mercury in primers in the military was pretty much a thing of the past, and commercial loaders in the US pretty much phased out mercuric priming before WW I. There were exceptions, though, with some match ammo made right up through the 1960s, mainly .30-06 and .300 H&H Magnum. These rounds were loaded specifically for match shooting, and the mercuric primer warning was printed on the boxes, along with a statement saying that the cases were not to be reloaded.


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Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
Hot soapy water works wonders!!!!! Not only good to clean ones self, but also your guns.. Go firgure!

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Dead [Black Ops]
 
Gary,

If I'm not mistake, the compounds in blackpowder fouling that cause rusting (potassium or sodium nitrate) are not soluble in alcohol.

Over the counter denatured rubbing alcohol contains upwards 30 percent water, and it's the water that does the drying.

You do, however, mention a nice after effect, which is that the alcohol helps evaporate any remaining water more quickly.

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Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
Hi, Guys,

Mike Irwin is correct.

Art, I don't think I ever said that. As Mike says, mercuric primers are a different ball game from corrosive primers. But some advertisers of ammo try to confuse the buyer by saying that corrosive primed ammo is "non-mercuric", or "non-corroded". Another term is "mildly corrosive". This is like being mildly pregnant.

If you want to know what will dissolve potassium chloride, the test is simple. If it will dissolve table salt, it will dissolve corrosive primer residue. If it won't, it won't.

Jim
 
Tatters:

If the ammunition you mentioned was fired in a pistol, pull the barrel, put it in a pot of water and boil it for a couple of minutes. Let it air dry, it will do this quite quickly, then clean as wou would having fired non-corrosive ammunition. If boiling or hot water isn't handy, plain water will dissolve the salt residue from chlorate primers, then dry and clean as above.

Corrosive primers were hard on barrels, didn't bother cases at all. Mercuric primers, rarely encountered these days didn't bother barrel steel, but would ruin brass in-so-far as reloadiung was concerned.

A friend of mine who used to shoot more bp than smokeless used to clean his muzzle loading rifles, some replicas, some original pieces with a solution of water and dish washing soap. He never had any rust problems.
 
Should mention that when I clean my smokepoles, I don't necessarily use a lot of elbow grease. I have the CVA Pump which pumps hot soapy water into the barrel. It features a plastic tube which you stuff up the barrel and is long enough to reach the breechplug of most guns. So, I do flush with hot soapy water and oil afterwards. The denatured alcohol is used to keep the fouling down and to wipe down the gun prior to hitting the road home.

For modern guns, I recently purchased some galvinized metal funnels with spouts. The funnels are original British Issue Equipment designed for flushing out the bore of the SMLE without exposing the stock to water. No reason why it can't be used on modern bolt actions.
 
Gary,

I made a device out of surgical tubing that I connect to the kitchen faucet. The other end has a small nipple that threads into the touch-hole liner on my flintlock.

I hook everything up, turn the water on to its hottest, and walk away for about 5 minutes.

After that length of time, the barrel is well heated (I keep the water heater up pretty high because of the dish washer). I let it drain for a few minutes, then run a couple of dry patches down the barrel, then oil lightly.

While the barrel is still warm, I take a rag with some Johnson's Paste Wax and rub it all over the barrel. This does a GREAT job of protecting against rust, and it also really brings out the lustre of the plum brown I have on my Renegade.

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Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
Guys

I treat ALL foreign ammo as corrosive, and use a cleaning regimen similar to what is already posted. Anywhere the firing residue, smoke, or gas has touched needs to be cleaned. I use boiling water with detergent, alternating with Sweet's 7.62, washed out with boiling water between stages. Then some Hoppe's #9 Bench Rest, to clean out any other residue, and finish up with Break Free CLP.

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God and soldiers, we adore
In times of danger, not before
With the danger safely righted
God is forgotten, and soldiers slighted
 
Mike, thanks for the "reprint"; sorry I wuz wrong in the credits. (But Jim's a sharp guy, too.)

Do you know when the larger military weaponry ceased using "fulminate of mercury" in cannon shells, etc.? The mines around Terlingua were a major world source of mercury, until the beginning of WW II. By 1942, the mines were about played out, losing that source; yet I've read that the price of mercury fell at about that time.

Thanx, Art
 
Art,

Military cannon priming compositions are, apparently, significantly different from small arms priming compositions.

I'm assuming that they would have used mercury as the initiator at one time (potassium chlorate is, I believe, an oxygenator), but I have very very little information about primers for the big guns.

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Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
The piece of steel has, in fact, rusted around the place where I fired the Polish ammo, but not the spot where I fired the copper cased(Chinese) ammo.
I guess I need to adapt to a new way of cleaning if I am to use this ammo. No biggie, though, just a couple of more steps.

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"Any world that I'm welcome to.....Is better than the one I come from"
 
If you fire each and every gun each and every day, does corrosion have a chance to build?
 
PF,

Yes, it certainly can. Rusting from corrosive ammunition can start in as little as a few hours given the right atmospheric conditions.

Also, corrosive residue rarely stays just in the barrel. It can get into the action, on the breech face, and if the gun is a semi-auto, into the gas system.

When I worked at the gunshop, a man brought in an AK variant that he had shot with corrosive ammo, and then threw into the back of his truck for a couple of weeks. In Washington, DC, metro, where it is VERY humid in the summer, this is a big problem.

The action was firmly rusted shut. The gunsmith actually put the butt on the floor and KICKED the operating handle to get it open. The action creaked like a rusty garage door hinge.

Inside the barrel was OK because it was chromed, but the gas system was almost a total write off.

------------------
Beware the man with the S&W .357 Mag.
Chances are he knows how to use it.
 
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