mephisto
Member
Help. I am having a conversation, argument, with a couple of guys at work over corrosive ammo. What does it mean? :banghead:
Help, corrosive ammo?
- Thread starter mephisto
- Start date
- Status
Cacique500
Member
J Miller
Member
Corrosive ammo is ammo that contains fulminate of mercury as jsalcedo said. This unto itself isn't bad, this can be some of the most accurate ammo around. And if you keep your gun clean there is no problem at all with it.
Several years ago I bought an Ishapor Enfiled in 7.62 NATO. The instructions said to use Windex or some other cleaner with amonia to de-activate the corrosive properties of the priming mixture.
Unfortunatly the amonia plays havoc with brass cases so these need to be hot soap and watered as soon as possible if they are to be reloaded.
Several years ago I bought an Ishapor Enfiled in 7.62 NATO. The instructions said to use Windex or some other cleaner with amonia to de-activate the corrosive properties of the priming mixture.
Unfortunatly the amonia plays havoc with brass cases so these need to be hot soap and watered as soon as possible if they are to be reloaded.
Mike Irwin
Member
OK, quick primer (hahahahah! I kill myself...)
Mercury fulminate does NOT make a primer corrosive in the sense that's being talked about here.
The compounds that cause the rusting of steel are potassium salts, potassium chlorate, to be precise.
When the primer explodes, the chemical reaction converts some of the potassium chlorate into potassium chloride, which is a kissing cousin of salt (sodium chloride), and like salt, is hygroscopic. That means that it will draw water from the air to itself.
Obviously, if corrosive priming pulls water from the air, which then ends up in the barrel of your gun, you're going to have rust.
But, because potassium chloride is hygroscopic, that means that it's also very easy to use water to remove it.
Hot soapy water is recommended. The hot water increases the soluability of the potassium chloride, making it easier to remove, while the soap helps displace any residual oil in the barrel under which potassium chloride could hide.
The military stuck with corrosive primer compounds until the 1940s, because they were reliable and stored well.
Commercially, though, corrosive primers began to be largely phased out in the teens and 1920s. That's when you had brands like Staynless hitting the market.
Now, back to mercury in primers.
The problem with mercury isn't that it causes rusting in the gun, it's that it weakens the brass.
In the days before smokeless powder this wasn't a problem. The blackpowder residue helped dilute the mercury, and the low pressure BP rounds didn't drive the mercury into the case.
With smokeless powder, though, there was no real residue, and the higher pressures forced the mercury into the brass, causing brass embrittlement and case failures.
The Army discovered this problem in the late 1880s early 1890s after adopting the .30-40 Krag.
Army procedure was at that time to take back all ammo that had been fired in training and reload it for more training.
When the reloaded ammo got back to the troops, there was a high incidence of case failures.
After some study, it was realized that the mercury was the cause. Beginning by 1898, mercuric primers were being phased out of military use. Their use in the civilian sector continued for some years, but normally only in blackpowder rounds where it simply wasn't a problem.
By WW I, though, virtually all American commercial centerfire ammo was loaded with mercury free primers.
Some match ammo WAS loaded with both mercuric and corrosive primers right up through the 1970s. Somewhere at home I have a box of .30-06 match ammo that is labeled "corrosive and mercuric -- brass is not to be reloaded."
Mercury fulminate does NOT make a primer corrosive in the sense that's being talked about here.
The compounds that cause the rusting of steel are potassium salts, potassium chlorate, to be precise.
When the primer explodes, the chemical reaction converts some of the potassium chlorate into potassium chloride, which is a kissing cousin of salt (sodium chloride), and like salt, is hygroscopic. That means that it will draw water from the air to itself.
Obviously, if corrosive priming pulls water from the air, which then ends up in the barrel of your gun, you're going to have rust.
But, because potassium chloride is hygroscopic, that means that it's also very easy to use water to remove it.
Hot soapy water is recommended. The hot water increases the soluability of the potassium chloride, making it easier to remove, while the soap helps displace any residual oil in the barrel under which potassium chloride could hide.
The military stuck with corrosive primer compounds until the 1940s, because they were reliable and stored well.
Commercially, though, corrosive primers began to be largely phased out in the teens and 1920s. That's when you had brands like Staynless hitting the market.
Now, back to mercury in primers.
The problem with mercury isn't that it causes rusting in the gun, it's that it weakens the brass.
In the days before smokeless powder this wasn't a problem. The blackpowder residue helped dilute the mercury, and the low pressure BP rounds didn't drive the mercury into the case.
With smokeless powder, though, there was no real residue, and the higher pressures forced the mercury into the brass, causing brass embrittlement and case failures.
The Army discovered this problem in the late 1880s early 1890s after adopting the .30-40 Krag.
Army procedure was at that time to take back all ammo that had been fired in training and reload it for more training.
When the reloaded ammo got back to the troops, there was a high incidence of case failures.
After some study, it was realized that the mercury was the cause. Beginning by 1898, mercuric primers were being phased out of military use. Their use in the civilian sector continued for some years, but normally only in blackpowder rounds where it simply wasn't a problem.
By WW I, though, virtually all American commercial centerfire ammo was loaded with mercury free primers.
Some match ammo WAS loaded with both mercuric and corrosive primers right up through the 1970s. Somewhere at home I have a box of .30-06 match ammo that is labeled "corrosive and mercuric -- brass is not to be reloaded."
Mike Irwin
Member
JS,
A lot of people just assume that mercuric primers are corrosive.
That's actually a pretty good assumption, because corrosive priming continued in use for many years after mercury was phased out.
But it's not the mercury that causes the problems with rusting barrels.
You'll still fairly easily tie into recently made (within the last 20 years) foreign military ammo that has corrosive primers.
Much of the suplus that has come out of the former Communist bloc and out of the Middle East is corrosive, no doubt about it.
But, I don't know of any NEWLY manufactured ammo in the US, foreign or domestic, that is corrosive or mercuric primed.
I have a simple rule of thumb....
If it's US military surplus (excluding .30 Carbine, which never used corrosive primers) that is pre-1960, I clean as if it is corrosive primed.
If it's foreign military surplus and doesn't have the NATO acceptance stamp on it (the cross in a circle, and headstamped from a manufacturer in a NATO nation) I clean as if it is corrosive primed.
It only adds a few minutes to the cleaning ritual, so there's no reason not to do it, really.
Now, one thing you're going to occasionally see in advertisement is "mildly corrosive." I know a lot of people have problems with that term, saying that it's the same as being "a little pregnant."
In a way, it is, but mildly corrosive generally means that there's not a lot of potassium chlorate used in the priming mixture, so while it will still cause rusting, the extent of the rusting won't be as great.
Other ammo, especially a lot of it made for or in Middle Eastern nations such as Turkey, Syria, and Egypt, is WILDLY corrosive! The primers must have tons of potassium chlorate in them. The extent of the rusting can be extremely dramatic if you don't thoroughly clean after shooting.
A friend had one of those Helwan pistols some years ago, and a bunch of either Syrian or Egyptian surplus 9mm.
He shot about 50 rounds through it, and tossed it under the seat of his truck, and promptly forgot about it for about 2 weeks in the middle of a very hot, very humid Pennsylvania summer.
When he brought it to me it was impossible to cycle the slide, the magazine was stuck, and pretty much the entire thing was encased in rust.
After several days in an ammo can of penetrating oil, we got the magazine out and the gun disassembled.
The barrel was absolutely shot. Very little rifling could be discerned among the pits.
The rest of it was salvagable, if only barely.
We cleaned it up, buffed it down, and he painted it with Brownell's baking lacquer.
As far as I know he still has it, but he got rid of the rest of the Syrian ammo!
A lot of people just assume that mercuric primers are corrosive.
That's actually a pretty good assumption, because corrosive priming continued in use for many years after mercury was phased out.
But it's not the mercury that causes the problems with rusting barrels.
You'll still fairly easily tie into recently made (within the last 20 years) foreign military ammo that has corrosive primers.
Much of the suplus that has come out of the former Communist bloc and out of the Middle East is corrosive, no doubt about it.
But, I don't know of any NEWLY manufactured ammo in the US, foreign or domestic, that is corrosive or mercuric primed.
I have a simple rule of thumb....
If it's US military surplus (excluding .30 Carbine, which never used corrosive primers) that is pre-1960, I clean as if it is corrosive primed.
If it's foreign military surplus and doesn't have the NATO acceptance stamp on it (the cross in a circle, and headstamped from a manufacturer in a NATO nation) I clean as if it is corrosive primed.
It only adds a few minutes to the cleaning ritual, so there's no reason not to do it, really.
Now, one thing you're going to occasionally see in advertisement is "mildly corrosive." I know a lot of people have problems with that term, saying that it's the same as being "a little pregnant."
In a way, it is, but mildly corrosive generally means that there's not a lot of potassium chlorate used in the priming mixture, so while it will still cause rusting, the extent of the rusting won't be as great.
Other ammo, especially a lot of it made for or in Middle Eastern nations such as Turkey, Syria, and Egypt, is WILDLY corrosive! The primers must have tons of potassium chlorate in them. The extent of the rusting can be extremely dramatic if you don't thoroughly clean after shooting.
A friend had one of those Helwan pistols some years ago, and a bunch of either Syrian or Egyptian surplus 9mm.
He shot about 50 rounds through it, and tossed it under the seat of his truck, and promptly forgot about it for about 2 weeks in the middle of a very hot, very humid Pennsylvania summer.
When he brought it to me it was impossible to cycle the slide, the magazine was stuck, and pretty much the entire thing was encased in rust.
After several days in an ammo can of penetrating oil, we got the magazine out and the gun disassembled.
The barrel was absolutely shot. Very little rifling could be discerned among the pits.
The rest of it was salvagable, if only barely.
We cleaned it up, buffed it down, and he painted it with Brownell's baking lacquer.
As far as I know he still has it, but he got rid of the rest of the Syrian ammo!
Leatherneck
Member
Mike takes all the fun out of being uninformed, doesn't he? 
TC
TFL Survivor
TC
TFL Survivor
Mike Irwin
Member
"Mike takes all the fun out of being uninformed, doesn't he?"
Just because you can't read doesn't mean that he can't, Leatherneck!
Just because you can't read doesn't mean that he can't, Leatherneck!
J Miller
Member
Mike,
Since I'm one of the dumb bells who really got it all wrong, if you don't mind I'm gonna save your "primer" to a text file for reference.
J
Since I'm one of the dumb bells who really got it all wrong, if you don't mind I'm gonna save your "primer" to a text file for reference.
J
Mike Irwin
Member
Not a dumb bell, J Miller.
You knew that mercury in the primer was a problem, you just weren't quite right on why it was a problem. No harm in that.
Mercury fulminate is, however, errosive as all hell. It explodes with such force and heat that it when it was used pretty much straight in the early guns (like the pill bottle lock) it would pretty quickly fry the old soft iron and steels used in gun making.
It's not uncommon to see the nipples on old muzzleloaders looking pitted and fried, which is the result of the heat and force of the mercury fulminate percussion caps.
I don't mind at all if you save this.
You knew that mercury in the primer was a problem, you just weren't quite right on why it was a problem. No harm in that.
Mercury fulminate is, however, errosive as all hell. It explodes with such force and heat that it when it was used pretty much straight in the early guns (like the pill bottle lock) it would pretty quickly fry the old soft iron and steels used in gun making.
It's not uncommon to see the nipples on old muzzleloaders looking pitted and fried, which is the result of the heat and force of the mercury fulminate percussion caps.
I don't mind at all if you save this.
- Status
Similar threads
