pyrodex

[Mad Monk]

When you add up the chemicals listed in the open disclosure you see a total of 76% of the formula weight.
The so-called proprietary (read secret) ingredients are:
dicyanamide 5%
Sodium benzoate 19%

The dicyanamide acts as a pre-combustion rust (corrosion) inhibitor.  It is however destroyed by heat during the powder combustion process.
Sodium benzoate is also used in a few fireworks applications.
Alone with potassium nitrate the sodium benzoate would not burn fast enough to be of any use in a propellant powder, let alone as a low-pressure explosive compound useful in other applications.  That require the use of a healthy amount of potassium perchlorate in the formulation.

During powder combustion the heat decomposes the dicyanamide evolving cyanide gas.  When I( worked in the large chemical plant I handled 40 pound bags of it.  Got a close look at the warning labels printed on every surface of each bag.  Avoid fire or flame.  When heated to decomposition temperature evolves highly toxic fumes of cyanide.
Outdoors no problems.  Indoors with poor ventilation you might get sick.  Been there and done that !!!

Any propellent powder or primer composition based on a perchlorate will produce extensive micro-pit corrosion with any metal.  The corrosive action will depend on the relative humidity the post-combustion residue is exposed to.

Mad Monlk

[Mad Monk]

To prep for he next message.

When you patent something you patent a concept.  In the case of the original Pyrodex patent the concept was the use of sodium benzoate as a fuel in a low-pressure propellant composition that would also have use as an explosive composition.

While this sodium benzoate "fuel" had been used in model rocket motor experiments and in a few fireworks applications it had not been developed and patented as a low-pressure propellant powder able to replace black powder.  So that left a "window" in the basic concept that could be exploited.

Mad Monk

[Mad Monk]

In the early 1990's we watched in-line action muzzleloaders gain acceptance and sales.  But most of the in-line action crowd hoped for near smokeless velocities out of what is legally a muzzleloading weapon.  In addition.  The Pyrodex patent was due to expire with the 20 years of protection gone.

So Hodgdon went back to the lab to imprtove upon the basic concept to create a powder that would give higher velocities in the in-line rifles.  They came up with the 777 powder.

As soon as it became available I was able to purchase a container.  Took it apart in the wife's kitchen after suggesting she spend the day shopping at the mall.
Took some apart in water and then another sample in solvent alcohol.
Compared to Pyrodex.
More charcoal.
No sulfur.
No potassium perchlorate.

Then an alcohol soluble fraction that gave me interesting crystals.  A flame test showed it was sodium based.  Their products of combustion information showed a sulfur-based chemical after powder combustion.  So a little digging in the HazMat book showed it could be sodium trinitrobenzene sulfonate.  Commonly used in the manufacture of organic dyes and used in low-order detonating compositions.  This kitchen chemistry analysis was later verified and expanded upon by a buddy working in the main ATF forensic chemistry lab.

Then the logic behind the 777 formula made sense.  And the people who worked on this to get it to market had to have been fairly sharp.  This sodium trinitrobenzene sulfonate is highly reactive with charcoal.  That means that they could do away with the potassium perchlorate needed in the Pyrodex formulation based on the sodium benzoate.  They then also did not need the dicyanamide to prevent unfired charges from attacking any metal the charges were in contact with.  Compared to Pyrodex.  The 777 is a more stable composition not easily degraded if the powder picks up a bit of moisture before being fired in the gun.

But.  The ignition temperature of the 777 is a bit higher than that of Pyrodex.  That makes it bit less touchy when it comes to any accidental ignition events.  Another but here.  When I looked at the 777 and how fast it burned in the open I was a bit shocked.  If you ignite a pile of Pyrodex, in the open, on a flat surface you see it opens burns a bit slower than black powder.  The 777 has a very fast open burn rate.  Equal to or a bit faster than a good black powder.

In my work I looked at corrosiveness on steel and brass plates.  Pyrodex residue would produce rapid and extensive pitting of the metals when exposed to air with a RH level in a certain range.  Side by side I saw no such metal surface pitting with the 777 reside.  No more corrosive than a good well made black powder.

Mad Monk

[oldfox]

That was an interesting read!  I have been using T7 in a T/C Hawken for quite awhile and have never experienced any rust problems..  Thanks Monk!

[Old Ford2]

Hello Mad Monk,
Thank you for your post, always informative.
Fred

[Mad Monk]

I should point out that with the high temperature of ignition you may see a fairly wide range in velocities with different ways of igniting the charge in the gun.

Black powder is fairly easy to ignite and ignites at a temperature lower than that required for the BP subs.  When you go from standard percussion caps up through magnum caps and then to a 209 primer you see a little increase in velocity with an increase in the "strength of ignition".  This is much more pronounced with the subs and especially with the Triple Seven.  In my work, using a mule ear lock on the 50 caliber Great Plains Rifle I had a 100 fps spread on muzzle velocity when going from a standard cap to 2 different magnum strength caps and then to a 209 primer.  This vat about 70 grains in the .50 caliber.

With the Triple Seven the powder has a higher combustion temperature compared to Pyrodex.  If you use too large of a charge you may see the formation of a glass-like deposit in front of where the projectile sat on the charge.  This may happen if the gas temperatures behind the projectile go above 1600 degrees.  That is where the potassium carbonate in the combustion residue melts to a liquid and then cools to a glass-like film that does not readily dissolve in a wet cleaning patch.  When that point is reached it is wise to reduce the charge a bit until the "skin" is no longer a problem when you go to load another charge and projectile.

Mad Monk

[Daryl]

Really good explanation and information - thanks once again, Monk.

[WadePatton]

Really good explanation and information - thanks once again, Monk.

and how.

Thanks MM, quite clear and easy to grasp and I don't has to become a chemist!   

[WadePatton]

...BP is really hard to come by where I live.  Thanks

paging the OP.  We still don't know where you live.  (WRT BP availability)

Here in the USofA (continental version) anyone of legal age can get BP to the door.  Just a few clicks of the mouse.  I just checked and the prices haven't changed since last year.   Whoohoo, may have to order more.

Long live the local supplier who puts up with the hassles, but for remote folks brown delivers.

[StonewallCreekOutfitters]

I would be quick go to the Hodgedon website and they will tell you that 777  is only to be used in rifles with nothing but a 209 primer this stuff should NEVER BE USED in soft steel barrels which any 12L14 WHICH INCLUDES COLERAIN ,RICE
CHARLES BURTON do not use it in these barrels I had a customer in Arkansas that blew his left hand almost completely off with 777 in a 15/16 50cal colrain 90gr with a round ball. I had another customer that bulged a barrel with it on a t/c renegade I had another customer that was using 75gr on a renegade with 2oz of shot on a turkey choke and destroyed a stock I had another customer that tested it in a conagraph 60gr of 777 in a 54cal round ball 1600 fps GO TO THE HODGEDON WEBSITE READ THE WARNINGS

[Virginiarifleman]

ill stick with a proven product that's been around hundreds of years . even if I have to travel to get it.

[WadePatton]

Thanks for the information Troy, I didn't know, but then i never had any designs on using anything but Goex ever again.  I'm going to put on FB for others who might not know.  I'd imagine there are plenty of folks who may own both types of front-loaders and might not think to fully investigate before loading a "soft" bbl with it.

I would be quick go to the Hodgedon website and they will tell you that 777  is only to be used in rifles with nothing but a 209 primer.
This stuff should NEVER BE USED in soft steel barrels which any 12L14 WHICH INCLUDES COLERAIN ,RICE
CHARLES BURTON do not use it in these barrels

I had a customer in Arkansas that blew his left hand almost completely off with 777 in a 15/16 50cal colrain 90gr with a round ball. I had another customer that bulged a barrel with it on a t/c renegade I had another customer that was using 75gr on a renegade with 2oz of shot on a turkey choke and destroyed a stock ...READ THE WARNINGS

[Roger B]

I have no personal experience with pyrodex.  Regarding it's use in flintlocks, I remember an article from many years ago that described how a noted shooter and builder (darned if I remember who) was getting good results in flinters by using a "duplex" load. He loaded a few grains of 4F first and then the pyrodex main charge.  I'm not advocating that practice, just throwing it out there for what it's worth. 
Roger B.

[Topknot]

Mlbrant, I will tell you my experience. I used to use black powder years ago with no problems whatsoever, then pyrodex when b.p. started to get hard to get around here. It didn't me too long to discover rust in my bore. I stopped using it then and there and went back to black. I was away from B.P. shooting for a few years, being a single parent does not leave much time for shooting or hunting, though I knew that one day I would again have enough time to get back to my favorite past time.. hunting and shooting. That time finally came in 2003, but I couldn't find any black powder around here. An associate at my favorite outdoor store recommended a brand new black powder substitute that had not been out long. IT is called 777. I was a little leary at first thinking it would rust my barrel, so I did some investigating and read all the hoop-la about it. It said it cleans up with water, contains no sulfur and that you should reduce your loads 15% compared to black powder. I said to myself bull- sh&%$@.  Well I decided to give it a try and I have never looked back.
It has been the best substitute that I have used with easy cleanup and no rusting as long as you completely dry the barrel and run a little oil in the bore after cleaning. I highly recommend it in a percussion system. I don't have to use nothing but a normal CCI percussion cap to get it to fire , no magnum cap of any kind. Now I cant tell you about  how it would perform in a flint gun , but I suspect it would be just as good as long as you primed with 3f or 4f black powder. That's been my experience and Im sticking with it.

                                                                                          topknot

[Bob Roller]

Once again the specter of the shoulder fired pipe bomb raises its ugly head.
Are there any warnings about barrels made from certified,purpose dedicated
steels?

Bob Roller

[Herb]

StonewallCreekOutfitters, I went to the Hodgdon site and did not find what you said.  I think you were referring to the use of Triple7 or Pyrodex PELLETS with 209 primers.  I found no mention of barrel steel.  They do tell you how to use Triple 7 in flintlock rifles and also percussion rifles.