If it is mercury fulminate in primers then it is not corrosive but it is errosive and cleaning after shooting have no effect about that. Is it corrosive "old style powder" residue or any other compound in primers ?

Jiri

It was the "salts" in the primer compound. The "mercury" primers were not as corrosive, but led to problems with the brass cases deteriorating.

Modern primer uses lead styphnate as main ingredient, but old primer compound use pyrotechnic mixture as source of ignition. They contain potassium chlorate, which after use becomes potassium chloride, this is the salt.
(Blackpowder produce a different salt, potassium sulfate)

Combined with water vapor in powder gas and in atmosphere, the salt accelerates rusting.

As Pyrotek said, it is the potassium chlorate in old-type primers that make them corrosive. In the days when people all used black powder, it was common practice to clean the guns with water, which not only got rid of the BP fouling, it also washed out the primer salts deposits. So, when smokeless powder became common, water was not being used for bore cleaning any more, and everyone thought it was "nitro-powder" fouling which was causing the bores to rust so badly. Hence such products as "Hoppe's No. 9 Nitro-powder solvent". It took almost 20 years for us to discover the real culprit here in the U.S., but the Swiss and Germans made the discovery, and changed to noncorrosive primers, long before we did. And the amazing thing is that we never found out about the German development before we made the same discovery about primers independently, long after the Germans and Swiss!! (It helps to be able to read and write in several languages).

[ 04-29-2003, 00:05: Message edited by: eldeguello ]

Thank you for answer.

I was studing chemistry but can't imagine someone would use KClO3 or similar salt producing oxidizers in primers.

I have another question.My friend have a press for making caps for muzzleloaders from bear cans. But problem is what to use in. The simplest is to make organic peroxides, but it is not way we would like go (non stable, reactive with metals, very, very dangerous). mercury fulminate is also easy to prepare, but it is erosive. Maybe lead azide with some flegmatizers and frictioun reducers. What is your opinion ?

People I know have used kitchen match heads. Also a mixture of powdered zinc and sulfur.

I don't think any of the various primer compounds are any more or less erosive than another particular primer compound. Any erosive effects noticed , I think, would come from the hard silica particles or something other than an organic or inorganic salt in the priming compound. There must be a reason other unstable and shock sensitive compounds haven't been commonly used as primers. You might be reinventing the wheel. That may not be a good idea unless there aren't any wheels around. Instead of thinking about using organic peroxides, think in terms of inorganic peroxides, like in potassium perchlorate for the oxidizer. Best-o-Luck

The potasium chloride does the same thing that potasium nitrate does in black powder. Potasium nitrate provides a solid oxidizer for the carbon and sulfer.