Corrosive Mil-surplus ammo and Mercury

[Bullseye22]

Since my son and I started our small collection of old mil-surplus rifles, I have done a lot of research on the use of corrosive surplus ammo. Since we have a Mosin Nagant 91/30, and a Chinese T-53 carbine, we have been shooting mostly Russian and Bulgarian spam can ammo. Recently with the acquisition of a Spanish M43 Mauser, we have been using some surplus Turkish ammo. We are very diligent in flushing the barrels out at the range with a mixture of Windex and Water (using an enema bottle) and giving them a full breakdown and cleaning when we get home. So far, no problems and no rust. But during a visit to the LGS yesterday, the owner advised that we should not be worried about the salt in the corrosive primer, but the Mercury. Most, if not all that I have read about cleaning firearms after using corrosive ammo has dealt with getting the salt our of the bore and off the bolt and other parts of the rifle. So have I missed something? Do I need to be worried about Mercury in the primer, especially in 1970-1980's Russian/Bulgarian surplus ammo?

Information

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[Parashooter]

Do I need to be worried about Mercury in the primer, especially in 1970-1980's Russian/Bulgarian surplus ammo?

1. No. Very few mercuric primers have been produced since 1950.

2. No. Mercuric priming has no harmful effect on the gun. It does spoil the fired cases for reloading.

3. No, there's no salt in a "corrosive primer". They contain potassium chlorate (not salt) that leaves a residue of potassium chloride (a salt) after it ignites.

4. No, you don't need the Windex. Water is all that's needed to dissolve the chloride residue and flush it out.

5. No, there's no need to flush the bore at the range - as long as you clean with water before nightfall.

6. No, your LGS owner is even more confused than you are.

[WarPig1976]

Shooting corrosive ammo really is a nonissue. There is NO need to clean the weapon at the range, with that said you do have to clean the bore and bolt the same day as shooting. Hoppes #9 says right on the label it dissolves corrosive primer residue the same with Balistol. One can also use a Black powder solvent which will no doubt dissolve the salts.
Poring boiling water down the bore is another "old school" option which I will say gets some big chunks of gunk out that you don't even know was in there, I tried it ONCE after it was discussed on another thread, pain in the *** but worked! Bottom line is corrosive ammo will not somehow rust out a barrel in a matter of minutes, just clean the weapon the same day.
Oh, all the mercury goes into our lightbulbs now...not primers..

[Bruce McAskill]

Mercury hasn't been used in primers in 100 years or so. The US military used to have many posts reload their fired cases so to extend the life of the brass the use of Mercury in primers was discontinued before 1900. Most of the military around the world found out the cost to use something other then Mercury much cheaper. So don't worry about Mercury in any of the normal surplus ammo you use.

[Bullseye22]

Thanks for the replies. I had never heard of Mercury in the primer, but you never know until you ask the "experts". So, that is why I asked the question here-where I know I'd get expert advice.

[WarPig1976]

I'm not an expert at anything but, I did sleep at a holiday Inn express last night...

[browningautorifle]

One thing that was missed here, the fulminate of mercury primers were used originally to extend the life of the primers in storage. Of course better things were discovered and they went the way of the Dodo...

[Bruce_in_Oz]

One quick way to ID priming compounds is to look at the primer cup.

If it is brass "coloured" it is ALMOST certainly "non-mercuric". If it is "copper" coloured, it is almost certainly Mercuric"

Why?

As regular users of Mil-Surp (Brit/Oz/Indian) .303 ammo find out, the brass, even if the ammo looks perfect, starts to develop cracks within weeks (or less) of firing.

This is because, on ignition, the mercury in the priming compound is "liberated" and suddenly sprayed at high pressure all over the front end of the case. Mercury has the annoying property of breaking the copper/zinc bond in the brass. This is "NOT a good thing".

That is why "mercuric" primers have "copper" cups; the mercury does not react with pure copper. If you look at early US made cartridges, like .44-40 and .45 Colt etc, a LOT of them have copper primers: these are soft and thus easy for early springs and mechanisms to ignite. They also probably contain Mercuric fulminate and interesting compounds that form REALLY corrosive salts upon ignition.

Our German cousins pretty much perfected "non-mercuric" (LEAD based) primers before WW1. The non-corrosive thing came a LOT later.

The biggest boost was the M-1 Carbine. Because these beasties had a "non-user-serviceable" gas system, they NEEDED "non-corrosive" ammo. Not just any old "non-corrosive" ammo, but "MIL-SPEC", first time, everytime sort of ammo.

Put simply, Mercury is the cause of brass embrittlement. The "salts" that are added to the brew in order to extend the "brissance (flash) of the primer are what causes the corrosion. My Canadian associates tell me that much of the "Great, White North" is so dry in the winter, that there is insufficient moisture in the air to combine with these salts to start corrosion. The onset of "Summer" somewhat changes that scenario.

With the advent of 7.62 NATO, it could never be anything BUT Non Mercuric, non-corrosive, apart from the bogus stuff produced in China, Bulgaria, Russia and several other "not-quite-NATO" countries over the years.

As for reloading Berdan primed brass: it is a lot more of a fiddle than processing Boxer cases, but, if Berdan is what you have in bulk, it CAN be done. The biggest problem these days is finding the primers.

RWS used to sell a wide range of brass-cupped Berdan primers:

RWS 6000 was THE primer for .303 Mil cases that used the 1/4" diameter, primer,

RWS 5608 was the "Mil-Spec" primer for virtually every major European military cartridge, not to mention Australian L2A2 7.62 NATO ammo.

RWS 5627 is the nickel-plated, slightly thinner-cupped version of the 5608 and works in a HUGE range of European Ex-Mil and sporting cartridges.

RWS also made a slightly bigger (only by a couple of thousandths) primer than the 6000; this was perfect for Russian 7.62 x 54 cases, as well as quite a few "odddball" English and European "express" cartridges.

Alcan in the US ONCE made/sold a wide range of Berdan primers, but probably not for a long time now.

[Bruce_in_Oz]

Quick follow-up:

Lots of info on Berdan primers here:

Berdan Primer Suppliers and Dimensions

If you are ever offered FN .303 ball or tracer ammo dated in the early 1950', GRAB it.

It uses the smaller (5.5mm / .217") RWS 5608 or 5627 primers. The original primers are non-mercuric and easy to remove, especially with "hydraulic" systems. After "de-crimping" the pocket, subsequent depriming is a breeze, either with the nifty RCBS Lachniller tool or a carefully ground, 3" "Ramset" nail used as a chisel. It is also a lot less messy, but there is a chance of damaging the anvil.

That's the good thing about the bigger .250" primers; there is more "wiggle room" when using the chisel method of removal.

Removing the .250" copper primers after the first firing generally has to be done hydraulically. There is often sufficient crimp to hold the primer in so tightly that the chisel tears out through the soft cup as you begin to lever it out.

However, if you have more patience and dedication than money, it can be worth the effort.

[WarPig1976]

Thanks Bruce!! added as a bookmark for future reference.