Re: reloading
In the mid 1980s a friend and I opened a "tin" of 45 acp that was sealed in 1943. It shot fine.
I have shot my own stuff I made in the 1970s a couple of years ago. It was still on target. I didn't shoot any of it over a chrono the last time. But I have measured some a few years ago that was still the same as it was when I put it up.
Keeping everything clean and dry is the main thing. After you get the rounds assembled, it just needs to stay dry & cool. Or at least not hot.