I know this has been beat to death

and have used magazines in this last year or so that I loaded in the early 80s and had no problems.

I read that Col. Cooper (I think it was him) had some 1911 Mags. that were loaded prior to WWII and when he returned they functioned just fine. Maybe someone else has that info.

I had two Glock G30s magazines (10-shot) that were almost impossible to load to full capacity. I finally forced them fully charged and left them a month. Now loading the 10th is as easy as the 5th. So that says something about spring relaxing.

Then again, another far connected story about springs. I know a guy who's uncles were playing in an old house. One found an old rusty Daisy BB gun in the attic and pointed it at his sibling and pulled the trigger. It was loaded and cocked for who knows how many years. The rusty BB penetrated the boy's eye and he lost it due to infection. So that was some spring! The boy that lost his eye is now in his late 70's, if he's still around.

Lots of variables in the 1911 magazines as to design and quality. Types of followers and base plates, springs used. It's hard to say. The GI mags are certainly the low bidders and a very conservative benchmark. I think the Italian magazines are ahead of the game as to quality and design. They have been making guns some 600+ years!

the actual movement under load and the release.

Left a 45acp mag loaded for about 10-11 years. That spring failed to feed full mag.