Do what you will, but if it were mine I'd shoot it. I've used powder a lot older than that. What matters is if it's good, not if it's old.

I have the remains of the keg of WWII surplus 4831 that my Father bought circa 1968. It smells ok, no brown rust in the powder, and I load a couple '06's with it every few years for nostalgia reasons. How long it'll stay good is anybody's guess, but I'll continue to use it as long as it does.

On the other hand, two weeks ago I sprinkled a full pound of IMR4831 (that a buddy gave me a while back) on the grass because it had gone bad (the powder not the grass!) - unopened since it was made 20-30 years ago. Go figure. (Of course I can't attest to the conditions it was stored in before it came to me. All my powder lives in cool dry circumstances.) I cried because my 6.5x55 loves it and I can't find any for sale.

Edit: thought of another anecdote. 10-12 years ago I came into an old can of SR-80 (the fore runner of 4759) that had to date to the 1930's. Being inquisitive from having read a lot of stuff about reloading from before the War, I had to try it. It smelled ok, and shot quite well in a Springfield with cast bullets.

How old is not as important as how it's stored and temperature it's stored in. I also have old powder that's from WWII surplus that I still use and stored in my basement that's dry and cool it shoots great.

I had a old can that when poured let off a yellow dust ! Strong smelling. I torched it!

My opinion only. With gun powder availability and pricing I understand more reloaders reluctant to throw a can of old spoiled powder in the garden. But other than the smell if you find old powder turning reddish and rusting the can I personally would throw it out. When it turns reddish and acidic it's turned and may shoot but not as designed and made. 

Some powders like Winchester/Olin ball powders have a coating on the balls that retards the rate of ignition. This is specially formulated to make, what Olin called, a ' progressive burn ' which regulates the pressure curve down the barrel. During the process of ball powder deterioration this retardant coating decomposes first so the powder lites off faster than it should. This may create a serious pressure problems with hot loads. 

Stick powders, according to my old neighbor Frank Snow, ( founder of Sierra Bullets ), deteriorates faster because of increased surface area created by the hole in the middle of the kernels. During WWII the USN had problems with stick powders they stored at Subic Bay in the Philippines and had to dump tons of it due to deterioration and guns that were acting up. 

According to Frank Snow and others such as Homer Powley, ' Unique '  is probably the most environmentally stable of powders as it is pretty much water resistant. 

Rick

calledflyer wrote on Jun 22^nd, 2025 at 1:07pm:


Please accept my apology if it read that way. It was not my intention at all. I guess sometimes I get immersed in some technical crap and forget the way it can impact the OP's original intent. 

Rick

I know the replies have all dealt with smokeless. 
Black powder. I have cans of Goex 2F, 3F, etc from 1992. Stored  properly and it’s no different from new.

FWIW, a few years ago I reloaded and fired an original .56-50 Spencer cartridge using the original 155+ year old powder. Check out my video to see how it went.


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