# Stored powder and energy loss



## bigbr (Oct 24, 2007)

It was a few years back, but I spent hours fine tuning my loads and sighting in the old smoke pole only to find out that after only a year everything had changed. The Elephant brand black powder had lost an average of 75 feet per second across the chronograph with the exact same loads as I had used the previous year. My shots were low and erratic on paper and I was at a loss as to why. 

Just out of coincidence I use a new lot of the same powder that a friend had just purchased from our supplier and found that the same load was closer to the velocities I was getting the year before. I have always been meticulous in my storage of all of my gun powders, and especially my black powder and substitutes. However, as I tested my substitutes, stored from a year or more earlier, I found a similar phenomena. The most popular Pyrodex, seemed to be worse energy loss than the Elephant brand black powder. 

Wow this was interesting.....I thought. A buddy of mine had introduced me to a new product at the time called Clean Shot BP substitute. Over a period of a couple of years we started comparing stored powders and found that there is and was a loss of energy in stored powder. The Clean Shot BP substitute, although lost less of its energy, still proved to be noticeable across the chronograph. A valuable lesson learned.

The following is a excerpt from a post that I am borrowing that really seems to explain things better in laymen terms:

“Gunpowder contains charcoal (finely divided carbon), sulfur (yellow powder), and potassium nitrate (saltpeter). 

The latter is a crystalline solid similar to table salt. It is mildly hygroscopic, namely, it absorbs moisture from the air. This renders the gunpowder far less effective, and possibly hard to light. 

Hence the term "keep your powder dry". Gunpowder needs to be stored in airtight containers.

Note that potassium nitrate, KNO3, is perfectly stable chemically. It does NOT react with water to give potassium hydroxide and nitric acid to any extent. That is a characteristic of any salt of very strong acids and bases, as this is.

Also, from memory, guncotton is used for modern propellants. That is cellulose nitrate, a substance easily made by soaking cotton wool in a mixture of concentrated nitric and sulfuric acids overnight, then washing extremely thoroughly, until free of residual acids. If the cotton wool is allowed to dry thoroughly, then it can be ignited by a match or a spark. It vanishes in a puff of flame and smoke. It was a favorite bench demonstration of mine for some lectures, such as chemistry for geologists and metallurgists.

The substance can be compressed and molded or extruded into shapes, such as rods, or cylinders with holes along them; that allows control of the burning rate, which is necessary for the propellants in guns that fire a projectile shell.

But the guncotton is slowly unstable on exposure to moist air. It depends, I seem to remember, on the completeness of removal of residual acid from the product.

Cellulose nitrate, or nitrocellulose is the nitrate ester of the hydroxyl groups along the cellulose chains (put simply, polymerized glucose). On exposure to moisture in the presence of acids, acid-catalyzed ester hydrolysis occurs, releasing nitric acid and cellulose.

This makes it unstable and also unreliable.”

When trying to get the best groups and consistency out of that front stuffer, little things do matter and especially with black powder and substitutes, Yes even the new super-duper substitutes, will lose energy over time, some just faster than others. Keep your powder dry and good hunting....Bigbr


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## legacy (Sep 30, 2007)

Dang! That's one more thing to buy!!! Interesting and good information....Thanks!


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## campfire (Sep 9, 2007)

Thanks for the information. So are the plastic boxes that pyrodex pellets come in air tight enough to prevent/slow deterioration or would it be better to store pyrodex, perhaps box and all in a Tupperware or comparable container or even a zip lock bag?


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## bigbr (Oct 24, 2007)

*Re: Water tight military ammo boxes*

I do not think that the plastic bottles seal well enough. I use water tight, (with the rubber seal) military ammo boxes.... with descant for long term storage.
Bigbr


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## ridgetop (Sep 13, 2007)

Very good info., thanks. I have noticed that my pyrodex pellets will hangfire for just a split second after keeping them for more that a year. I have tried to seal them off in freezer bags but it hasn't worked.


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## flyfitch (Sep 22, 2007)

I shouldn't have bought a dozen bottles of Pyrex in bulk from Costco last year. That is good to know though. I am glad you reported that.


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