Powders & humidity
- Thread starter jski
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I'd keep it in climate controlled environment if you can. This is the best info I can find on this.
http://bulletin.accurateshooter.com/2008/09/tech-tip-humidity-can-change-powder-burn-rates/
http://bulletin.accurateshooter.com/2008/09/tech-tip-humidity-can-change-powder-burn-rates/
Orcon
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SAAMI recommends powder to be stored in "a cool dry place" but I've not seen anything more specific than that.
Toprudder
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Last sentence in that report: "You’ll find it has lost a bit of weight from the water baking out."
While I can't argue with the results of his testing, I have to wonder about that last statement. Are there not solvents in the powder that could "bake out", possibly more readily than water?
Interesting article, though.
Good point but I really have no idea. I just keep my powder cool and dry.Last sentence in that report: "You’ll find it has lost a bit of weight from the water baking out."
While I can't argue with the results of his testing, I have to wonder about that last statement. Are there not solvents in the powder that could "bake out", possibly more readily than water?
Interesting article, though.
quest4perfection
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After years away from shooting (1969, VietNam), I got into reloading knowing how moisture can do harm to most everything metal and electronic. So I chose the smallest and most seldom use storage space, sealed it off, and use it to store ammo, firearms, primers, powder. Running a dehumidifier runs up electric bill but I set the humidistat to optimal, knowing that all is well.
Smokeless powders are very stable. Humidity and high temperature will accelerate their decomposition and so are best avoided or minimized.
That would be desirable, but not necessarily mandatory.
Because of being sidelined for a while due to a neurological condition, I have partially used containers of:
- Bullseye
- Red Dot
- Green Dot
- Blue Dot
- Hercules 2400
- IMR-4198
- IMR-4227
- DuPont 680
- Hi-Skor 700X
Beginning in 2014/2015, I checked the powder. There was no rust color in it and the smell was still right. I started reloading cartridges with it. I then compared cartridges loaded in 2014/2015 with cartridges loaded with the same powder prior to 1993.
The DuPont 680 could not be tested as I no longer had an M1 Carbine. But amongst the others, almost all 2014/2015 cartridges returned chronograph results that were essentially identical to what had been loaded two decades or more earlier and were consistent with velocities recorded in the 1990s. The exceptions were Green Dot which returned velocities 40% lower than the loaded cartridges and IMR-4198 which returned velocities that were - after accounting for the statistical "noise" - about 5% lower.
So, in at least one situation, powders stored under less than ideal conditions for as long as 37 years generally looked, smelled and performed the same as they had decades earlier. So, are high temperature and high humidity bad for powder, yes. How bad? My experience is that they will accelerate the rate of deterioration, but not by a whole lot.
George P
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When I lived in the arid West, I kept them in my garage with no issues. Now, living in the VERY humid (and hot) Southeast, I keep powders and primers on a shelf in a bedroom closet - just to be on the safe side. Like a poster or two above, some of mine were purchased in the 80s and 90s and still go bang with the same velocity as before.
FWIW, many plastics are hydroscopic, meaning they will absorb some moisture. Typically, less than 5% by weight.
So I would assume powder is going to absorb some moisture, and in a climate with significant variation in relative humidity, like MN, expect to see 1%-2% variation in throw weight winter to summer.
So not much in the grand scheme of things. However, I do have to avoid taking some things (like powder) from a climate controlled environment to an uncontrolled one, since condensation can be a significant problem with a severe change in temperature or a small change in temperature and a large change in RH.
https://www.ptonline.com/knowledgec...n-Types/Hygroscopic-VS-Non-Hygroscopic-Resins
https://en.wikipedia.org/wiki/Hygroscopy
So I would assume powder is going to absorb some moisture, and in a climate with significant variation in relative humidity, like MN, expect to see 1%-2% variation in throw weight winter to summer.
So not much in the grand scheme of things. However, I do have to avoid taking some things (like powder) from a climate controlled environment to an uncontrolled one, since condensation can be a significant problem with a severe change in temperature or a small change in temperature and a large change in RH.
https://www.ptonline.com/knowledgec...n-Types/Hygroscopic-VS-Non-Hygroscopic-Resins
https://en.wikipedia.org/wiki/Hygroscopy
quest4perfection
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Never leave in hopper between load sessions, cap tightly...all else has been mentioned;
just saying
just saying
Blue68f100
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Didn't we just have a thread where the used tested a few powders in the extreme cold. If I recall the W296/H110 did not drop off like this data shows. So I'm questioning where some of its due to air density in combination with temp.
I store my powder and primers in separate foot lockers in my basement (actually an in-door access storm shelter). The top of foot lockers are not air tight but my basement is always dry and cool. I still put a couple of silicone bags in each foot locker just to keep humidity in check. It has worked well for me.
spitballer
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I stash my powder and primers in a 5 gal bucket with a can of Damp-Rid.
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