I was reading about this and found this post by Mike Daly, the customer satisfaction rep at Hodgdon:
I was hoping to find some comparison tests online with BP vs Pyrodex on the guns themselves, but no luck. Sounds like it definitely makes a difference in brass, although Photobucket ate the photo.
Read this:
http://www.cascity.com/forumhall/index.php/topic,56362.0.htmland this
http://www.chuckhawks.com/doc_white2.htmnote that Doc White said:
"DOC: The residues left from black powder combustion include sulfates, carbonates and nitrates, all in the presence of water due to hygroscopicity of the fired residue. The sulfates can form sulfuric acid, the nitrates nitric acid, and the carbonates the weak carbonic acid. All can eat away at metal if left long enough. Fortunately, the amounts left in the barrel are usually small and relatively weak, and are only a problem if left for a long time. This is in addition to the rusting effect of the water, which is the worst problem, relatively speaking.
Pyrodex is basically black powder enhanced with chlorates (an old time trick used as early as 1800), which adds the problems associated with hydrochloric acid. This acid is the reason Pyrodex can etch stainless barrels. The result is, as more water vapor is thrown into the residue, the worse the problem; not only because of water-induced rust, but also from acid etching."
note that acid etching is peculiar to Pyrodex, and not Real Black.
and this:
http://www.cascity.com/forumhall/index.php?topic=43136.0---
In fact, I will repeat what I wrote in 2012:
Please remember that
1) Mike works for Hodgen and is an official spokesperson - an official spokesperson for a company has an obligation to defend that companies' products.
2) Your mileage will vary based on region and humidity.
3) your experience in an easy-to-clean cartridge arms for one year of use is far different from the experience of Hivernaughts
who used it in closed breech muzzleloaders, Please do not deride or belittle the actual reported and documented experiences
of others.
4) the issue of Pyro corrosion vs BP corrosion is more correctly compared to the difference between the effects of hydrochloric acid vs sulfuric acid: both are corrosive, but in different ways.
5) Whilst I prefer real BP, I do have and will use Pyro if I am short of BP and availability of BP is uncertain - I then use Pyro in cartridge guns and or C&B pistols and make a concerted effort to meticulously clean my smokepoles immediately with very hot soapy water, and oil them thoroughly with plain old oil.
6) I can and do take except to Mike's following statement:
Mike Daly wrote:
>Those who want to continue to spew about their “expert” knowledge about the corrosiveness of Pyrodex and how
>it magically micro-pits barrels are going to continue to spew the same old tired stuff. How could the continue to be the
>anonymous “expert” hiding on the internet if they gave up. That is just the nature of the internet. I (we) are bound by
> truth, the “experts” are bound by their imaginations.
Mike Daly should be ashamed of such Marketeer BS and semi-anonymous derision.
I myself have been been in discussion with chemists and gunmakers who investigated corrosion caused by Pyro.
They ARE experts in their fields. I do not believe Mike has the background in chemistry and metallurgy that these gentlemen have.
I myself saw the photos and "microscopic" photos of the crossections of barrels and breeches that were dissected in their work. The pattern of corrosion caused by the perchlorate residue in Pyro was clear and evident, and in fact can be differentiated from corrosion patterns from BP. Pyro corrosion was "finer" and more rapid than corrosion caused by BP. The facts and data are clear and irrefutable. This led several well known makers of Very High End custom flintlock rifles to declare that Pyro should not be used in their rifles.
If Mike wishes to call me a liar and a scoundral to my face I will gladly entertain the encounter, and I will come prepared with physical data and evidence and expert testimony that will stand up in any court in a Libel case. BTW I myself am no stranger to legal actions regarding strict and limited liability, tort law, contract law, patent law, and libel law.
Microscopic cross-section analysis is not new and it is not the hoodoo that Mike Daly seems to think. It is widely used in materials analysis, failure analysis, and there are many experts in the field who can be called upon as "expert witnesses" to testify under oath in a Court Of Law. Those who are familiar with the subject matter in a particular field often become so expert that they are able to identify a particular corrosive agent by the pattern it leaves in a particular material.
The Perchlorate Residue corrosion from Pyro is nothing new - that residue was the problem with "corrosive primers" over 100 years ago.
It has been demonstrated that the perchlorate residue from Pyro (which is the corrosive culprit) can be difficult to dissolve - it will not dissolve in modernisch fancy solvents but is fairly readily removed with hot soapy water, and lots of it.
I will once more offer my small treatise on the topic:
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. Others more conversant than I in the exact chemistry may wish to chime in.
Pyrodex contains, among other things Potassium Perchlorate. That is the material with which
people take issue. Unfortunately, contrary to Mr. Daly's protests, it *is* Chemical Science!
But any chemist (and any advanced chemistry student) who is sufficiently schooled in
metallurgy and corrosion can understand and explain it.
It has been proven in various scientific studies 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 of the time.
Anyone who has been around firearms for more than a few years should be familiar with this.
It is because of this particular "perchlorate corrosion" 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*
- Both BP and Pyrodex are corrosive. But not in the same way.
- Both can be cleaned - but 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.
Further, depending upon humidity, Doc White ( see above) has written that Pyrodex can and does cause the "etching"
that Daly claims does not exist.
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 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".
However the fact remains that Perchlorate residues are corrosive, in a manner different from BP, and if left uncleaned
can cause serious damage, and that microscopic chemistry is in fact at play.
Ah one more tidbit:
Mike Daly Wrote:
>NASA and the DOD both have tested and used Pyrodex over the past 35 years. Their testing contradicts the “experts” on the >internet. They found Pyrodex to be no more corrosive than black powder.
I have searched for any such tests, documentation, reference, or even any mention to any such tests of Pyrodex and corrosiveness, and have found nothing.
I have access to nearly every non-classified DOD and NASA doc ever published and have not found anything.
I challenge Mr Daly to provide those test documents, if they in fact exist.
yhs
prof marvel