I have recently picked up a couple of used third generation S&W pistols that had two springs on the guide rod of each pistol. One spring appeared to be a standard recoil spring and the other spring was a somewhat smaller spring that fit inside the recoil spring. Once this was on a 4516-2 and the other time it was on a 4013. Both guns function normally with this set up, but I just have never heard of this and to find it on two different guns from two different parts of the country seemed a little strange.

Is anyone familiar with this setup or why someone might put this on a pistol?

My only guess is that the recoil spring was no longer strong enough and they just added the smaller spring to give it a little more strength.

At this point I plan to order some new springs from Wolf for the guns, but I am just curious about this set up.

S&W engineers finally decided that the right spring rating for the compact .40's & .45's required the newer style non-captive, dual nested spring combination. (I asked once.)

The same current dual recoil springs are used in the 4013TSW/4040PD and the 4513TSW/457, as well as the later production 4516 such as yours, as I recall. The current springs have a light blue paint code and are called 'inner' & 'outer' springs in their parts listings.

If you check the Wolff website you'll see the following info:
"Recoil Spring
For Use in:
4013*, 4014*, 4053*, 4054*, .40 S&W
4516, 4516-1, 4536, 4556, 4596, .45 ACP (Call for 4516)
* Not for Rev. 4, dual recoil spring models."

Last time I checked they weren't making a dual spring set which would fit in the later revision models of the 4516 series, and one doesn't seem to be listed on their website at the moment. (As you can see, there's nothing listed for the 4516-2.) There was a change in the guide rods when the springs were changed, too, as I recall. Neither do they seem interested in making the dual spring setup for the 4013TSW model, either.

Then again, last time I called and asked S&W about the older single recoil spring for the older 4516 models (one of our guys had one) I was told they weren't stocking them anymore (so Wolff would seem to be a good alternative).

You can download the .pdf format Parts List from S&W and compare the different springs (and guide rods) used in the different compact .40/.45 models, and call S&W and ask someone to look up the differences for your -2 revision of the 4516.
http://www.smith-wesson.com/wcsstore...ist_Retail.pdf

__________________
Ret LE Firearms inst & armorer

Thanks for the information. That helps a lot. It is a set up that I was not aware of but getting two of them from such divergent sources had me curious. I guess since both pistols function just fine, I would do well to leave this set up alone and if I replace it to replace it with similar dual spring set ups.

I know this is an old thread, but I have some useful information. Brownells has both the inner and outer spring listed on their website. I just ordered an inner spring and backordered an outer spring.

Well, I appreciate you sharing the info. On my way to Brownells now.

Thanks!

Dave