I've reloaded for a while, then stopped due to reasons. What is the expected self life of powders, specifically Accurate Arms Powders?
A long time. I had some in my barn for over 10 years that was still good. There was a thread a while back that had some suggestions to tell when it's bad, an ammonia smell or something? I'm not sure, someone will be along with that soon.
Well…….lots of folks shoot ammunition made during WWII so the question is just how long ago did you make these rounds? 
I've loaded some 4350 that was from the mid 1980's not long ago, no issues. If it was a partial or not much left in the can I'd just dump it, odds are it won't be consistent with a lot that's years newer.
for sure if its like pyrodex i had a can for at least 10 years till used up and bought another.
I agree if stored in a reasonably climate controlled environment shelf life is measured in decades. If it was not stored properly it will have a strong acidic order. The smell will be nothing like good powder.
Before I knew better
I had some unique and the primers to go with it stored in a cardboard box on a shelf in a barn. It had been opened and partly used at the point of going into said box. It sat there for 8-10 years.
I loaded it up and shot it without issue and discontinued storing those items outside.
Perhaps I got lucky, do the smell test.
If it smells funny, you think it looks funny.
It makes superb fertilizer for roses.
Better safe than sorry.
Stored in ideal conditions it can go past 100 years. Hercules was storing some of the original lot of Bullseye in deionized water. As a QC check they'd pull a sample, dehydrate it and compare new production lots to it. Alliant is probably still doing this if any of the original lot is left. I have seen data sheets that said "indefinitely" on them for shelf life but I don't think any of them do these days.
I've never seen powder go bad since I used to store it in the house and now it's in the garage shelter which is pretty temp stable. Hot temps will degrade it faster but I think it's the wide swings that really amp up the degradation. The military stored ammo in basically what were metal shipping containers in the sandbox. Storage life is measured in decades like others have said as long as conditions are reasonable.
I've never seen powder go bad since I used to store it in the house and now it's in the garage shelter which is pretty temp stable. Hot temps will degrade it faster but I think it's the wide swings that really amp up the degradation. The military stored ammo in basically what were metal shipping containers in the sandbox. Storage life is measured in decades like others have said as long as conditions are reasonable.
