dahermit said:
The subject of the post is whether or not a magazine spring will take a set over time. The only way a spring will lose its "temper" is with the application of heat...nothing to do with taking a set.
The subject wasn't whether springs would lose "temper" or take a set, but whether springs can degrade with use and eventually lose their ability to function as intended.
New coil springs will always take a set when first put to work -- you can see this with both recoil springs and magazine springs. That's
normal spring behavior, and it's understood and taken into consideration by the folks who specify the springs used in a given gun design.
We've had this discussion here on
The Firing Line a number of times, and folks who haven't taken part in those earlier discussions (and a few others, like Bill DeShivs, ) continue to claim that only inferior springs fail; they also seem to believe that all springs are designed with the same objectives and are all intended to have long functional lives -- regardless of how the spring or the gun is intended to be used.
Engineers involved in this discussion in the past -- at least one of whom was a metallurgist -- tell us that while steel is surprisingly resilient (and flexible), it will degrade if it's pushed, stretched, or bent too far.
These experts also reminded us that this behavior is seen in almost all materials -- wood, steel, aluminum, glass, rubber, nylon, etc. That's why buildings fail, bridges fall, airplane wings break off, ropes fail, rubber bands break, and mirrors or windows crack. (Aluminum, for example, doesn't bend well -- it typically breaks very easily -- and that's why there are few aluminum springs.)
In the case of recoil and magazine springs -- both types of coil springs -- the degradation takes the form of small fractures in the metal where it flexes. As the work continues and more metal fractures, the remaining (sound) steel is forced to take over the work being done and the failures cascade. I don't think the degraded metal has lost it's "temper" -- it has just been broken by "over"-use (i.e., lost its structural integrity.) These springs get soft because some of the metal in the spring is no longer resisting when pushed or stretched. This sort of degradation doesn't happen UNTIL the spring is pushed to or beyond it's design limits (also called its
elastic limit).
Some designs (like 7-round 1911 mags) never push springs that far. Some very small guns, like the Rohrbaugh R9 recoil spring mentioned earlier, do. But many gun owners want extra capacity or a smaller gun size and don't mind having to replace springs more frequently.
When used as intended, many (perhaps most) springs may never degrade enough to cause a malfunction. But when degradation does happen the gun will start to "act up": a recoil spring that doesn't store enough force to close the slide, a magazine spring that may not lock the slide back, or when rounds in the mag nose dive and not freed properly.