It definitely sounds like your extractor spring is tired.
Big question here as you are asking about the 539 -- some of the early ones used a
very short lived different extractor than the hundreds of thousands of S&W 1-2-3rd Gens that used the standard extractor.
Look at the pistol shown in this discussion:
439 / 459 with short fat extractors
Does your 539 have an extractor that looks like that one?
If the answer is yes... then I honestly don't know what extractor spring that variation uses.
Some great folks on this forum will have the answers you need, but that is out of my area of experience.
However, if your 539's extractor looks like the ones in post #1 here:
model 59 with better pictures
...then a replacement extractor spring is simple, easy, fast and low cost too! Wolff Gun Springs has them.
https://www.gunsprings.com/SMITH%20&...D58/dID261#901
$3.49 and they will ship fast and cheaply also. We can walk you through replacement of the extractor spring.