My Colt GM purchased in 1946 for me by my Father, still uses the original magazine -- and my son shoots it on a regular basis. I used the gun for a hard ball gun when I shot bullseye.
A close friend has been in the spring business for about 45+ years, and when I worked for him a short time some years ago, I asked several questions about spring fatigue. His answer was that a properly made and tempered spring does not know if it is compressed or relaxed. GLV