powder storage: So what exactly does the "cool" in "cool, dry place" mean?

This may not help you, but my FIL has all his reloading equipment in a 10x10 bldg that is not climate controlled. He has never had any problems with powder going bad in the 22 years I have known him. Here in Kentucky it gets pretty hot and you can cut the humidity with a good pocket knife.

The military likes to store ammo in dry sealed containers at 55-60 degrees.

They'be been into guns and shooting for a very long time, so I'll trust their advice.

From our friends at SAAMI. Now as to the cool and dry I read it as an ambient temperature below 70 degrees F. and a relative humidity around 50%. Since the powder should be in a well sealed canister as long as the container is left closed external high humidity is not an issue. Temperature, however, causes powders to degrade and a faster than normal rate.

A thread search will also bring up likely a dozen old threads loaded with information on the subject. We have several members who really have the powder data down and on target.

Ron

powder storage: So what exactly does the "cool" in "cool, dry place" mean?

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In a word: basement.

Don

There have been times in my life in which I may have stretched the limits at storage being in the 90's, but always in a dark room out of direct sun light. I had to toss a pound once that that ad gone bad. So 90's isn't exactly ideal and would be risky for prolonged periods of time IMO.

But now days my powder lives in the same climate I reside in, which is to say no warmer than 78 degree's. And considering my wife likes the house pretty cool, 72 - 74 degrees my powder is probably good for a pretty long time.

GS

evtSmtx said:

As summer arrives in south texas I wonder about storing powder in a room off the garage. I now have a supply of powder that will last into the fall. This room get's into the 90's if it's 110F outside. Am I risking ruining powder? The storage room is "sort of" insulated and has no direct sunlight.

What about for the one powder that I use rarely? Those 2#s may take a few years to go through.

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Air conditioning is your friend. 90 degrees is pushing it as that is not "cool" What is your humidity?

Today it was 93F and about the same humidity until it rained

I gather your living area is not under A/C? If you have A/C store it there.

If you need a fan or ac, then it's no longer "cool".
You can push it, but there's gonna be a tiny bit of degradation.

Your man cave would be "cool " and hopefully dry.....

AFAIK no powder mfg has described "cool".
But I keep mine in a 2nd bedroom, AKA my man cave.
(in the house with a/c is good)

In the house is safest, and small amounts of smokeless powder are pretty safe.

In my reloading annex, it gets warm, but not extremely hot. I keep some powder in a small cooler on the floor (warm air goes up) and its always cool to the touch when I check it.

Kept in a back corner in the dark of my closet. Right next to my Igloo full of tasty aging cigars! Right at 70*!

dark, cool, and quiet.

be safe

If you are comfortable, your powder & primers are comfortable.

If you are hot and sticky, your powder and primers will be uncomfortable.

Just keep them where you are comfortable and they will be fine.

rc

Hondo 60 said:

AFAIK no powder mfg has described "cool".
But I keep mine in a 2nd bedroom, AKA my man cave.
(in the house with a/c is good)

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See post 4 above and

http://www.hodgdonreloading.com/reloading-education/safety/gunpowder-stability

They all say cool. True, Cool is not defined as a temp but I think any reasonable person (as they say) would not think cool is 90 degrees

What is "room temp" defined as?? Most say around 75 degrees.

Bottom line, powder does deteriorate faster the hotter it gets. Cold it will last indefinitely..

Info I've read is powder deteriorates at a higher rate after 86 degrees F and rapidly after 104. Still if you'd load and shoot it in just a couple years it'd probably not go "bad". Best kept at cooler temperatures though. This discussion has some good points and a chart that's interesting.
http://forums.thecmp.org/showthread.php?t=157820

Rule 3 it's relative, when I was in the ME, and the day time temp was 130+ F, when it dropped to 100F at night, that was darn right cool.

I store mine in my man cave, gunpowder on one side, primers on the other, I keep the AC at 75 in that room.

If you are comfortable in the room where the powder is - you're fine. I would avoid attics (too hot) or basements (usually too humid). If your house is air conditioned and heated - no problem.

The OP asks an interesting question, and the answers are even more interesting. Everybody seems to have an opinion, but I noticed nobody's opinion is linked to any published specifications from the mfg. While I'm sure that heat and moisture can eventually break down powders, I am very skeptical as to how sensitive they are, and how long it takes just based on my own experience with "improperly" stored 30+ year old powders I still have.

Has anybody seen any actual published mfg data that lists specific temperture and moisture thresholds?

I had some powder that had been out in a garage for several years. 110+ in the summer, and down to -20 in the winter.
It looked fine, smelled fine, and as it turns out...it shot fine, too!
But these were sealed containers, and next to zero humidity.
I keep mine in the basement @ 70 or so just to be safe.

TimSr said:

The OP asks an interesting question, and the answers are even more interesting. Everybody seems to have an opinion, but I noticed nobody's opinion is linked to any published specifications from the mfg. While I'm sure that heat and moisture can eventually break down powders, I am very skeptical as to how sensitive they are, and how long it takes just based on my own experience with "improperly" stored 30+ year old powders I still have.

Has anybody seen any actual published mfg data that lists specific temperture and moisture thresholds?

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How about this?: From ADI powders which makes many powders for Hodgdon.

http://www.adi-powders.com.au/handloaders/faq.asp

25c=77F
10c=50F


What is the recommended way to store my powder?

Store smokeless powders in their original containers, which have been approved for that purpose.

Keep in a cool dry place separate from solvents, flammable gases and other combustible materials. Ensure that the storage area selected is free from any possible source of excess heat and is isolated from open flame, hot water heaters, furnaces, chimneys, flue pipes, etc. Avoid storing smokeless powders in areas, which may be heated by the sun or where electrical, electronic or mechanical equipment is operated. Do not allow containers of powder to contact walls of storage areas where the outside wall is exposed to sunlight or any other form of heating. Any such form of heating may result in spontaneous ignition, either immediately or at a later stage, due to accelerated chemical deterioration. An average storage temperature below 25ºC is recommended to obtain a safe shelf life of at least ten years from the date of packing. Increased storage temperature will reduce the safe shelf life significantly - by approximately one third for every 10℃ above 25℃.

Storing gun powder in the house never seemed like a good idea.
Even though it's rarely more than just a few pounds, I sleep better with it elsewhere.
Our previous house had a detached garage, but our current one has the typical dumbo attached two car version.
(Terrible idea, with just drywall between spare bedroom and cars).
And that's where the powder is.
Even with previously opened containers, it doesn't seem to suffer from being there.
About 80-85 degrees in summer and 40-50 in winter.
Some of it, the Pyrodex for muzzle loading, must be twenty years old and still looks and smells good.
Gun powder must be tougher than we imagine.
And lots safer than all that gasoline in the cars.

TimSr said:

The OP asks an interesting question, and the answers are even more interesting. Everybody seems to have an opinion, but I noticed nobody's opinion is linked to any published specifications from the mfg. While I'm sure that heat and moisture can eventually break down powders, I am very skeptical as to how sensitive they are, and how long it takes just based on my own experience with "improperly" stored 30+ year old powders I still have.

Has anybody seen any actual published mfg data that lists specific temperture and moisture thresholds?

Click to expand...

We do have a member or two who normally contribute to these threads with actual data and test results involving powder storage and powder degradation across temperature and humidity ranges.

A forum search of "powder storage temperature" will bring up dozens of threads on the subject and for someone with the patience to read it all some actual data and numbers.

Ron

The cool dry place and "data" from ADI which makes the powder is not sufficient?

How much can cool dry be beat to death?

I provided a lot of information on this topic in the above referenced CMP thread, which apparently, none of the subsequent posters visited.

Danger with Deteriorating Powder

http://forums.thecmp.org/showthread.php?t=157820

The bottom line is that gunpowder is deteriorating the day it leaves the factory. It is a high energy compound that is breaking down to a low energy compound. It is just following immutable thermodynamic laws. Temperature accelerates the breakdown of gunpowder, it follows an exponential function: which happens to be the Arrhenius equation. The hotter it is, the faster it breaks down.

Humidity effects gunpowder as there is a lot of water in the air. Right now, humidity is pretty high outside. Gaseous water condenses and evaporates on the powder grain, and the polar covalent bonds of water interact with the double bonded NO molecules. They also wick nitroglycerine to the surface which will spike the pressure curve. Nitroglycerine also attacks nitrocellulose, and it turns out double based powders deteriorate in less than half of the time of single based. Any ionic compound accelerates the deterioration of gunpowder. So, it ain't just water, but there is one lot of water around.

I don't know how dry to keep gunpowder or just how much humidity starts to effect gunpowder lifetime. Someone else needs to find data on this.

Based on the chart I posted on the CMP page, keep your powder below 86F and it should last 45 years for single based and 20 years for double based, assuming the powder was properly made. Powder lifetime is so variable that it can't be predicted with any real accuracy, so first world militaries pay people to go through their stockpiles and pull out munitions before they become dangerous to use, and dangerous to store. http://www.smallarmssurvey.org/weap.../unplanned-explosions-at-munitions-sites.html This is a huge activity, about $1 billion in munitions are discarded by the US every year. I have seen estimates of hundreds of thousands of tons demilled per year, the US demill stockpile is 587,000 tons, and I think that is the back log. http://www.smallarmssurvey.org/about-us/highlights/highlight-rn37.html Ironically, the anti gun, anti war group, the Small Arms Survey has the best open source information on munitions lifetime and explosions.

There are all sorts of old coots who claim their old gunpowder will last forever, because their expectations are they are going to live forever, therefore their powder hoard must last forever, but they don't actually know how much stabilizer is left in their powder. Some of these people are going to awake up to a burning house, assuming they wake up at all.

Old gunpowder will blow up your firearm and autocombust, burning your house down.

My powder, and primers stay in my reloading shop. It's climate controled, and stays around 71* in the summer, and 69* in the winter with humidity around 49-52%.