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I asked a question about Pyrodex residue being alkaline
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I asked a question about Pyrodex residue being alkaline
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Oct 8, 2025 at 5:17pm todddoyka and shootist---Gary like thisReplyQuoteEditlikePost Options
Post by Bullshop on Oct 8, 2025 at 5:17pm
I asked if Pyrodex residue was alkaline and got this great and complete answer.
November 10, 2015, 11:44:34 PM
I was searching for my dissertation on BP vs Pyro, and found it! Not on my confusicator, but out on the interwebs.
So here it is again:
Regarding the Cleaning of Guns After the Use of Pyrodex and 777
( both of which utilize potassium perchlorate )
Real Black Powder contains sulfur and potassium nitrate and charcoal. On combustion we get gasses (which propel the bullet) and
byproducts of incompletely burned material (fouling). Both are corrosive due to the resultant chemicals formed.
Pyrodex contains, among other things Potassium Perchlorate. That is the material with which people take issue.
Many have complained, "Awe come on we're just shootin stuff- , this isn't Chemical Science here!"
Unfortunately it *is* Chemical Science. Any chemist (and any advanced chemistry student) who is also schooled in
metallurgy and corrosion can understand and explain the difference in corrosion vis-a-vis chlorates and steel.
It has been proven in various scientific tests that when fired in a gun, the residues from Potassium Perchlorate (whether via "corrosive primers" or via any powder mix), are particularly corrosive to steel (not so much to wrought iron) at a microscopic level
and is particularly difficult to stop once this corrosion gets started. This was very well known in the early 1900's and became the topic of the "corrosive primers" discussions in the past.
It is because of this particular "perchlorate corrosion" associated with Pyrodex that people are upset.
The big advantage In My Opinion to Pyrodex is that it is not classified in the same manner as BP, and thus
is treated in the same manner as Smokeless for transport and storage. To quote my Chemist friends:
"Potassium perchlorate is a low-order detonating compound. But when you mix it in with a bunch of other things
it is now longer capable of going low-order detonation." .... (Thus it is less sensitive than BP) .
Also "Compared to potassium nitrate, the potassium perchlorate simply provides more oxygen in a shorter period of time."
so you need to use less Pyrodex than BP *BY WEIGHT*
Thus we have established:
- Both BP and Pyrodex are corrosive. But not in the same way.
- Both can be cleaned - but Pyrodex must be cleaned quickly
one must pay attention to the nasty details.
the big issue is that if perchlorate salts are missed during cleaning the resulting corrosion is initially subtle but aggressive.
This sort of corrosion is more easily seen and dealt with in C&B revolvers than in closed-breech ML,
The corrosion is even less apparent if Pyro is used in cartridges.
I have contacts in the Very High End ML gunsmith community who have dissected modern made traditional ML rifles and
analyzed the corrosion to the Breech. To a man they are all able and willing to identify the unique perchlorate corrosion
and evaluate how badly the breech has been compromised.
The basic problem is clearly that the perchlorate residue has not been adequately cleaned, thus allowing corrosion to proceed.
Whether the corrosion is due to BP or Pyro is irrelevant. What is relevant is that the appropriate cleaning solvent was not used.
Lately the advert is that Pyro "is no more corrosive" than BP. That statement, whilst technically correct in some ways, is misleading
to newbies without telling them exactly what cleaning product *will* kill the "corrosive salts".
It is unfortunate that "back in the day" Pyrodex was in fact advertised and marketed as a BP substitute that did not require the kind
of cleaning that BP needs. That was both unfortunate and wrong, and we can blame the "marketeers" and their usual hype.
In fairness to the marketeers it is nothing different than advertizing that "Kedz Sneakers make you run faster and jump Higher" or
that "Koldgate toothpaste makes your smile whiter".
Unfortunately, once the product is purchased and used, the reality of the situation strikes home, at times with a vengence, and the
marketeers are nowhere around to pay the piper.
----
Regarding The Cleaning of Perchlorate Salts
It appears that it is no longer generally well known that "modern bore cleaning solvents" are not effective on chlorate salts; this does unfortunately include Hoppe's No 9.
It used to be generally well known that "hot soapy water kills the salts" - howver it is not really killed, but flushed away.
Some feel that that a strong lye soap is the key, whilst others maintain that the hottest water possible is the cure.
However, being a pragmatist, if one is using very hot soapy water "which one does it" becomes irrelevant
Some feel that the vinegar in Windex will do it, this I do not know.
whilst one fellow believes "Hoppes says right on the bottle 'neutralizes corrosive salts'", there is an excellent discussion seen here on THR:
(You need to Login or Register to view media files and links) with excellent points by Jim Watson, which if I may snip his statements:
-------------------------
Hoppes does not neutralize the corrosive salt (potassium chloride) from chlorate primers.
Nothing "neutralizes" the corrosive (chloride) salts, they are already neutral.
...
{{meaning, PH neutral which he later clarifies}}
...
The only reliable way to deal with corrosive primers is with water. You can dress it up with Windex or peroxide or emulsifiable oil,
but it is the water that dissolves the potassium chloride. Then dry and oil.
...
The research that showed what the problem was with newfangled smokeless ammunition came out in a paper titled "Corrosion Under Oil Films."
----------------------------
and he later states regarding Hoppes:
-------------------------
The corrosive residue from chlorate (or perchlorate) primers is potassium chloride, KCl.
That is what is known as a neutral salt, the product of reaction between a strong acid and a strong base.
A KCl solution is at or very near pH 7 which is as neutral as you can get. So you cannot neutralize it in a chemical sense.
...
Hoppe's main ingredients on the MSDS are kerosine and alcohol. KCl is not much soluble in either.
So you would be depending on it flushing out the salt physically.
...
----------------------------
In the book "Gunsmithing" by Roy Dunlap, the author writes:
"Water must be introduced to the chlorate or salt-containing primer mixtures ... Oil will not disolve salt..."
And A wonderful post by Jowen Lawson here:
pistolsmith.com/workshop/9338-soap-water-pistol-cleaning.html
briefly discusses the issue and the "fix" by the U.S. Army:
extremely thorough cleaning of the firearm using boiling water and Government Issue soap.
It is my opinion that the only "magical property" behind GI soap is that it is already issued
----------------------
Thus we can see that the solution (pun intended) is soap and hot water - In my humble opinion, the hotter the water the better.
Heats up all the metal and provides a self drying feature
More Hivernaughts than I can count have been cleaning their smokepoles after dark by the using simmering water from the pot on
the coals of the campfire. I do recall laughing hysterically at one hairy friend who mixed up his hot water cleaning cup with his hot coffee cup.
I am told by my Chemist acquaintances that soap is in fact a "surfactant" - ie: a mystical material that breaks the surface tension
of water and thus promotes or enhances the solvent action of the water.
WRT "harsh lye soap" referred to in the GI cleaning link - all real "soap" is lye and fat. I am told that Ivory is one of the last of the
true "soaps" on the market. I am unsure where the "harsh" part comes from.
Finally, this information vis-a-vis the most effective method of cleaning Pyrodex perchlorate residue. From my friend The Mad Monk, chemist and BP specialist:
"In dealing with Pyrodex residue the key is to use large volumes of warm water. Seventeen parts of potassium perchlorate in the powder. During powder combustion the oxygen atoms are released leaving a large number of crystals of potassium chloride scattered over the surfaces in the bore. This potassium chloride is poorly soluble in water. If anything else is dissolved in the water, other than a soap, the potassium chloride crystals are nearly insoluble in the water. The potassium chloride crystals are also kinda picky as to what kind of soap will encapsulate them to be carried away in the water if they don't dissolve. " He offers further discussion as substantiation but I expect I am overly verbose enough for most folks
Thus when shooting pyro, the advised method of cleaning according to my chemist friend is hot water and lots of it! I am sure that vigorous scrubbing with appropriate brushes will help as well, and any way that one can provide further access the better (ie: remove nipples from revolver cylinders, etc) .
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