Powder shelf life

Greetings,

I have started loading 9mm and have probably a 1/3 lb of N340 left from early 2000's.  It's been kept at a constant ~70ish temperature in a fairly constant not humid environment (the cap is screwed on the jug though).  What is the life of powder?  I bought new 4lb jug of N340 and thinking about mixing it in with the new instead of using it straight.

Shelf life for powder is like life for humans; some never make it past puberty, and some live to 90.   Personally, I would not mix it with new.   Open it, smell it, and if it looks good use it.   I've been lucky and have 50 year old powder that remains good.

Don

I would not mix the powders. When you open the new powder I would verify the loads before doing a mass loadup.

USSR wrote:Shelf life for powder is like life for humans; some never make it past puberty, and some live to 90.   Personally, I would not mix it with new.   Open it, smell it, and if it looks good use it.   I've been lucky and have 50 year old powder that remains good.

Don

I'm curious, what does powder smell like that has gone bad?

zanemoseley wrote:

USSR wrote:Shelf life for powder is like life for humans; some never make it past puberty, and some live to 90.   Personally, I would not mix it with new.   Open it, smell it, and if it looks good use it.   I've been lucky and have 50 year old powder that remains good.

Don

I'm curious, what does powder smell like that has gone bad?

Kind of like really acetone or vinegar.

Pour the old stuff into a single use aluminum cake pan. Look for clumps and give it a good sniff. An odor like vinegar means the powder is oozing acids. Use it up quick. If it’s clumpy and they don’t break up with pan jostling, the acids are on the surface and you have fertilizer.

also the appearance of rust like particles is a bad sign.. again fertilizer

I finally used up the case of old paper boxed Hodgdon 4831 surplus a few years back.. that powder was well over 45 years old and still performed very well. I had taken the precaution of moving it all from the paper containers to Qt. sized plastic medical bottles to seal it better.

a Friend just gave me a 8lb canister of Win. 760 in the old metal can. Never been opened till I checked it out,... still fine.. that was probably from the 70s

Some powders go bad faster than others.  I've had several old cans of IMR 4198 go bad over the years.  I have a 8 pound can of WWII surplus 4831 that's still good.  I have a lot of pre-WWII caliber .30 and 8mm ammo, the powder of which is fine.  

Good powder typically has the scent of acetone.  Bad powder will have a acidic smell, and red dust will easily evolve.

Thanks all!  It doesn't smell like the new stuff.  Probably closer to only a 1/4 lb so just going to pitch.