I just replaced recoil spring in my 4013TSW. Its about 1/4" longer than old one. This is outer spring i'm talking about. Instead of being perfectly straight like old one it has a slight bend to it. Is this OK? Shoot away? Thanks in advance.

Most old spring take a set at a shorter length...new tend to be longer till they take a set. Is this a factory spring or aftermarket?

Be sure to test for function, feeling to see if any binding is occuring. Pulling the slide totally to the rear. If not then you should be good to go.

I suggest you sent it to me and I'll shoot it until the new spring is the same size as the old one. I'll keep careful track of the round count so you will know when you should replace the next spring.



Seriously though dude...Particle migration!
The stress field resulting from the strain due to the compression of the spring is like any other gradient in nature -- nature will tend to migrate particles in such a way as to relieve that stress/lessen the gradient. Heat flows from hot to cold (temperature gradient), mass flows from high concentration to low concentration (concentration gradient) so the atoms in the metal lattice of the spring will flow to reduce the stress resulting from the strain. Reducing the stress (energy stored in compression) by particle migration essentially reduces the strain by changing the equilibrium length of the spring. As a result, particle migration causes the deformation of the material becomes semi-permanent.*



OK really serious this time...
Springs lose their strength over time/use...hence they get shorter!




*This was pulled from Yahoo Answers as an answer to "why do springs lose energy" And I have no idea what he's talking about!

I bought a well used 4506 a couple months ago, and ordered a replacement recoil spring for it. I was shocked at how much longer the new spring was compared to the old one, which was long past its serviceable life. Assuming you installed the new spring correctly and it passed a functions check, you are good to go.

Factory S&W spring. Good idea to check for binding and function by hand first. Thanks

The spring on top is the new one I just bought for my 4506, about 8 inches. The bottom one is the old one, which I can assume was the original January 1990 recoil spring. 22 years can certainly make such things lose a little size

Attached Images

IMG00123-20120128-0147.jpg (83.0 KB, 57 views)

Holy smokes! They must take a beating.

This is what came with my 4506 as new:
Regards,
BM1