Pyrodex Caused Corrosion

I have seen a number of references to Pyrodex and supposed corrosion attributed to it (all other variables having presumably been eliminated as the cause of the observed corrosion). Of course this made me a bit concerned. I've been using Pyrodex since it came on the market, notably Pyrodex P in my cap'n'ball revolvers and in my Thompson Seneca .36 rifle. All together many hundreds of rounds have been fired in each gun. The .36 is my squirrel/small game rifle of choice and my first BP handgun, Lyman branded Pietta, have been in use since 1975 and 1974 respectively.

Sometimes the Lyman goes several years in "standby" mode (as a test) being loaded with 5 and the hammer resting on an unloaded chamber with uncapped nipple. It usually rests in my safe but might come out for contemplation now and again. I live in a moderately humid climate, summers here often have temps approaching 98 degrees with 99% humidity. However, it does get a bit cooler in the house in winter as we have the thermostats set at 62 degrees. My house is anything but climate controlled.

Up until today, the Lyman had spent the last 7 years or so (likely 7 years 8 months) loaded and mostly untouched. I would think that this would have given the demons I call humidity and heat to work their deviltry through condensation and so forth. Because of the recent comments I was finally motivated to end the test (darn curious!) and see what horrible damage had taken place, unseen, over these many years. On my daily trip to a shooting place the short test was conducted with all 5 chambers firing the first time without hangfires or squibs. 5 rounds went downrange and 2 of the 5 hit the 80-yard target. That last surprised me as I wasn't taking much time to sight.

After driving around in today's humidity so that I could complete my chores, I finally got home and took a few minutes to clean the old girl up. I got out the bore light and examined the bore. No pitting. No surprises as it is very easy to clean the bore. I then examined the chambers. No pitting. Ok, so that might be attributed to a thorough cleaning every time the old girl goes out with me. Let me see between hammer and frame, places I likely miss in my rapid cleaning mode. Ummm, there is a little bit of gunk there let me scrape, er, wipe it away. Any pitting underneath? Nope.

I'm thinking it will take much convincing to get me to blame Pyrodex for corrosion damage on my firearms.

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Well, I'm not a chemist but John Kort tells me that Pyrodex contains potassium perchlorate which, you may recall, was in the old corrosive primers. Prompt cleaning with plenty of hot water, which I do, removes the corrosive element.

So, it isn't the Pyrodex, it is lackadaisical cleaning. This is the apparent view of the manufacturer based on this response to an inquiry on the subject.

Pyrodex is no more corrosive than black powder and no harder to clean than black powder. This has been proven by our testing as well as the Department of Defense and NASA as both have investigated the use Pyrodex for their uses.

The only way that there was corrosion on your firearms is that there was residue left on the metal of there was a lack of metal protectant on bare metal and the gun rusted.

There is no other explanation I can think of.

Mike Daly
Customer Satisfaction Manager

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