are any of them corrosive
like wolf, silver or brown bear, jsc etc.

No reports of current production Russian ammo being corrosive.

Nah, I haven't heard anything about any of the modern Russian .223 ammo being corrosive. It's far from being my favorite ammo but as far as I know it isn't corrosive. Some of it tends to be a bit on the dirty side though. If you were to buy some of the old Chinese Norinco ammo that still surfaces at times, you might use caution with it. I have heard a few reports about some of it being mildly corrosive, although I haven't noticed this myself with the limited use I've experienced.

-Charging Handle

There is no such thing as mildly corrosive. It is either corrosive or not.

Its like being pregnant or dead, either you are or you are not.

Yes, but some can be a bit worse than others, hence the mild wording. Is there a better term for the effect created in barrels by Norinco ammo? A buddy of mine used to have some problems in a Taurus PT-92 with Norinco ball ammo (green and white box). The effect wasn't as severe as some of the old surplus WWII ammo for example, but if not attended to within a few days would leave some type of yucky mess inside. It would clean up nicely with a little effort but I never seen what it would have done had it been allowed to go longer untreated. Perhaps this is actually a different type of reaction taking place which really isn't corrosive ammo in the same sense? Where did the "mildly corrosive" term come from?

-Charging Handle

OK. You I'll stick my hand in some 5% vinegar, you stick your hand in some 33% hydrochloric acid. They're both corrosive acids, right ? [;)]

No, again, it is either corrosive or not.  The substance (mercury salt) that makes it corrosive has no levels of corrosiveness.



Yes, corrosiveness. [:D]



It comes from dealers who are too chicken shit to admit that the ammo they have is corrosive.  I have been selling ammo at shows since '92, I deal closely with seveal distributors frequently mentioned on this forum.  They have freely admited this to me.  Corrosive is corrosive, but if they put [i]mildly[/i] infront of the word, it makes it seam better to the buyer, and increases sales.

I'll take that bet. [:D]

Seriously though, your comparison is of two different items.  What makes ammo corrosive is the same substance all around.  a quart 33% hydrochloric acid is just corrosive as a pint of 33% hydrochloric acid. See what I mean?

I get your point.  Anybody who doesn't just isn't thinking straight.

Correct.  



Partly correct.  

Mercury fulminate is/was an ingredient in many corrosive primers.  The products of mercury fulminate are either mercury metal (vapor) or mercury oxide.  Steel is not attacked by mercury or its oxide.  However, since chromium, as in chrome-lined barrels, does react with mercury to form a relatively fragile alloy (or amalgam, an alloy of a metal with mercury), mercury fulminate containing primers could theoretically be corrosive to these barrel.  But only some WWII primer formulations (not Norinco Chinese) contained mercury fulminate.  The latter has a shorter shelf-life compared to chlorate formulas.

What causes corrosiveness is the potassium chlorate.  This supplies oxygen for the various reactions that occur in the primer and one of the resulting products is potassium chloride.  It is this 'salt' that is very corrosive to steel.  Potassium chloride is at least as bad in promoting rusting/etc. as sodium chloride (table or sea salt).  Chrome-lined barrels are much more resistant to potassium chloride than unlined steel barrels.

Formulations that contain mercury fulminate but no potassium chlorate do not affect steel barrels.  Other old formulations use potassium chlorate but no mercury fulminate.  An excellent (but brief) review of these formulas (mercury/chlorate/both) can be found on pages 454-458 of Tenney L. Davis' book 'The Chemistry of Powder and Explosives', 1943 available from Amazon.com for $25.  

Wolf, Silver or Brown Bear do not contain mercury fulminate or potassium chlorate.  They use 'modern' (widely available since at least the 50's) formulas based on lead styphnate.  However, some countries, notably China, have used potassium chlorate formulas well past the 50's because they are far cheaper to make.  

This is a complex topic and I could go on, but the point is this:

Corrosive = potassium chlorate, and, as obershutze916 put it, you either have corrosive ammo or you don't.  It's not a matter of degrees of corrosiveness.