Thread: Do powders change over time.

Yes they do change. As others have said, there can be differences between batches of the same powder, but long term the powders can change too, and I'm not meaning during storage (though they change then too).
I found 44gr of AR2208 was too hot in my 308 back in the early 1990's, had really sticky bolt lift. Starting load was 41gr and 45gr was book max back then in Nick Harvey's manual.
Nowadays I'm at 45gr with no issues. New powder (still AR2208 though), different primer and case, but same projectile from same box, and same rifle. The ADI website has the starting load at 44gr and max at 47-47.5.