I had hoped to avoid the topic of spring 'set.' You see, it depends on what your definition of 'set' is. Really. Lest there be odious comparisons of Slick Willie and yours truly, let me first point out that the word 'set' has the largest number of definitions of any word in the dictionary.
Here is what Wolff has to say re: spring 'set.': (URL: http://www.gunsprings.com/1ndex.html )
6. My spring got shorter after I used it for a short time. Is it bad?
Most new springs will take a set when they are first compressed. That means they will shorten up. This is a normal event and you should not be immediately alarmed. The greater the stress on the spring, generally the more set that will occur. All Wolff springs take this set into consideration. The ratings of the springs you receive are the ratings after the set has occurred. After set has taken place, the spring should remain essentially stable.
7. My lighter [recoil] spring is longer than the heavier spring for the same gun. Is this a problem?
Wolff offers many springs in different weights for the same use. Factors such as the size of the wire, the number of coils, the outside diameter of the spring as well as the free length determine the strength of a particular spring. Often, lighter springs are longer than heavier springs because lighter wires and/or a different number of coils are used. Free length is then adjusted to achieve the exact strength desired.
So, you see, a small amount of 'set' is normal. Every used recoil spring is shorter than a new one. As Wolff points out, this really is not cause for concern, as the ratings are adjusted for the initial 'set.'
So, how do you determine if a spring has too much 'set?' By the time this occurs, functioning will be impaired, and battering of the gun will be likely. Were I enamoured of a particular recoil spring (why, I can't imagine), I would compress it against a scale to measure the amount of force necessary to compress. I have never done this; I just toss them out, and put in a new one every 2,000 rds. or so. Likewise mag. springs. Cheap insurance.
What does anyone have to gain by seeing how long the cheapest part in your gun can last, at the expense of much more vital, and expensive parts? This doctor says use preventive medicine. Trust me, I am a doctor.
that one was for you, Rich
NRA Life Member since 1972, 1911 GC shooter since 1967 (Still have it, still pristine).