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Powder shelf life

drmarc

ToothDoc
Full Member
Minuteman
Feb 20, 2003
509
3
Hillbilly , Kentucky
Is there any general rule on the shelf life of stored powder, assuming it is stored in a climate control environment?

Thanks in advance..
 
Re: Powder shelf life

I'm currently using some pistol powder manufactured in the late 1950s by Hercules (now Hodgden), so I know from personal experience that 50+ years is NOT the limit. I know plenty of guys using surplus ammo from the 1960s, so the shelf life is pretty long.


Jeffvn
 
Re: Powder shelf life

Thanks for the quick reply Jeff.

I should have added, does peak performance degrade over time even though it still functionally works?
 
Re: Powder shelf life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: drmarc</div><div class="ubbcode-body">Thanks for the quick reply Jeff.

I should have added, does peak performance degrade over time even though it still functionally works? </div></div>

Unless somehow it can degrade like becoming stale etc.., I don't think it would..
 
Re: Powder shelf life

I agree. I was given some 2400 powder from the 60's, and it shot fine. I did notice that a max charge of today was an over pressure round for this powder. So, I backed off, and it works great. I use it for my personal 357 Mag rounds today.
 
Re: Powder shelf life

Just because one batch of powder lasted 50 years does not mean all will last that long.
Different kinds of powders have different lasting abilities.
Win ball powders are very chemicaly stable and will last a very long time . Other types not as long.
Storage temp has a lot to do with how long it lasts.
Powder breaks down in different ways. One way is that the coatings used to slow it down can break down and the powder speeds up as it gets older. It still might shoot ok but is a faster powder than when first made. This can cause excess pressures. As noted previously.
Common sense must be used when using old powders and inspect them before use. Any unusual smell or rusty appearance or powdery residue at the bottom of the tin may indicate oxidation or chemical break down of some kind.
Treat all very old powders with some suspicion and load as if you are unsure of the actual powder speed.
 
Re: Powder shelf life

So what is an ideal powder storage climate?
 
Re: Powder shelf life

Stable cool temp and low humidity is best. If you keep it in and old non working well insulated fridge and don't open it on hot days or maybe just for a very short time but in cool winter leave it open more often to remove any heat but dont let it freeze. Install a thermometer inside . It should maintain a fairly stable temp with the insulation involved.
A stable 50 F to 60F which is way below the average continental USA summer temp of 75 F should work ok as it is not so cold it could cause condensation.
Increased storage temperature will start to reduce the safe shelf life as you go above 77 ºF. For most smokeless powders .
 
Re: Powder shelf life

Would storing powder in a Cooler be better than just sitting on a shelf in the closet?
 
Re: Powder shelf life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Country</div><div class="ubbcode-body">Just because one batch of powder lasted 50 years does not mean all will last that long.
Different kinds of powders have different lasting abilities.
Win ball powders are very chemicaly stable and will last a very long time . Other types not as long.
Storage temp has a lot to do with how long it lasts.
Powder breaks down in different ways. One way is that the coatings used to slow it down can break down and the powder speeds up as it gets older. It still might shoot ok but is a faster powder than when first made. This can cause excess pressures. As noted previously.
Common sense must be used when using old powders and inspect them before use. Any unusual smell or rusty appearance or powdery residue at the bottom of the tin may indicate oxidation or chemical break down of some kind.
Treat all very old powders with some suspicion and load as if you are unsure of the actual powder speed. </div></div>

+1 on this,
I asked similar questions of PHD chemists that I work with,
and while they wouldn't give me a time frame, they all agreed that the powder would begin to break down to some extent, as it "off-gases" certain chemicals.....
 
Re: Powder shelf life

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: alan98</div><div class="ubbcode-body">Would storing powder in a Cooler be better than just sitting on a shelf in the closet? </div></div>
It depends wether the cooler is capable of insulating to a high enough degree to stop sudden increases in summer . Also how you open and use the cooler. If you open it on a hot day and the powder heats up then when you close it the heat will be trapped inside defeating the purpose.
Also you need to look at the location of the powder storage area. Is it on a wall that gets the sun?
Find the coolest place in your shed or basement that is dry and has low humidity and locate the cooler there.
Keep it closed in hot weather and open it up for a while in cold weather to remove any trapped heat.
It will be better than open storage , how much is hard to say.
 
Re: Powder shelf life

That's a great idea. Living in AZ the summers can destroy many things that need stored.
Thanks for that one