I have a 625-4 that had a reduced power mainspring installed years ago. I hadn't shot the gun for years because I got an occasional light strike, 1 or 2 out of 100 rounds. I'd like to put the gun back into rotation for matches, so I would like to install a factory mainspring and see if that helps.

I can get a spring from Gun Parts Inc, but times I pay tax and shipping your talking $25. Seems kind of steep to me!

Question is, any difference between K,L, and N frame mainsprings? I can find tons of K & L frame springs but not for an N frame.

Thank you for any input!

I believe that the N/L/K all use the same mainspring.

Another option is to try an extended firing pin.

I've used a Wilson Combat mainspring with an Apex extended firing pin in an L frame without any issues.

They are the same. That said I have quite a collection of them and there are many variations visible to the naked eye. If you replace the factory strain screw with an Allen head set screw and adjust the trigger pull to 8 1/2 pounds it will set off any primer. I have installed 35~40 of these with excellent results.

This has got the hammer mounted firing pin so I can't put an extended one in!

You probably only need a half turn or so to get 100% ignition. A full turn for a little extra insurance. The factory strain screw probable is seating in the valley of the aftermarket spring, so a longer screw is one solution. Just for the heck of it, I might flatten the valley with a hammer and anvil to see if that is enough. I personally prefer factory strain screws and factory springs although some of my Performance Center guns came with the springs with the valley in the middle, and they have worked fine.

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Richard Gillespie
FBINA 102

While i have never had this issue IIRC have seen members place a (shortened?) fired 22lr case over the strain screw to make it slightly longer.

A spent primer also fits.

Spent.

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- Post No Bills -

The spring in the gun is flat, I may end up fooling with the strain screw but before I do I would just like to start with a stock spring.

You can also bend any mainspring straighter to give it more force with the same strain screw. This works especially well for borderline ignition.

Edit to add: Or bent more for less force. A properly tempered spring holds the shape it's bent to.

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protocalldesign.com

If you still need an original spring send me a PM, and I'll send you a couple. Just send me the actual postage costs.

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H Richard
SWCA1967 SWHF244

Thank you very much for the offer, but I got one off ebay a couple days ago. Hopefully it will do the trick!

Don't assume the strain screw is the correct length, measure it.

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Stang1911

Never, ever, go to a reduced power mainspring. It is a receipe for misfires and squibs.

this is always worth reading:

IT DON’T GO BANG: FIRES, HANGFIRES, MISFIRES AND SHORT ORDER COOKS IN JERSEY
By Mark Humphreville

Replacing old mainsprings in M41' and Ruger MKII 22lr pistols, along with the recoil springs noticeably improved ignition reliability and feed and extraction. These are auto pistols, but I learned decades ago about not using weak mainsprings in my Ruger Redhawk. Yes the single action trigger was better, but infrequent misfires showed me weakening the mainspring was a bad idea. You want the most energy possible on the primer for reliable ignition.

There are all sorts of "new" mainsprings on ebay. I found a listing where the seller showed the WW2 military package that had ten or so K mainsprings. I was pretty sure based on the picture, cosmoline included, that those were NOS mainsprings. I put one into my K38, and the ignition appears snappier. I do notice Wolff has K/L/N frame mainsprings, don't go for reduced power unless misfires won't bother you.

People who play "combat games" can use the most sensitive primers, can adjust their ammunition to their pistols, so that a misfire does not ruin their score. However, change ammunition in those pistols, and don't be surprised if in cold weather, you get a squib! Bud of mine sold me his M586 which he used in PPC, and that's what happened to me. He told me he had fired 60,000 rounds, and used Federal primers, which are the most sensitive primers on the market. I was firing my ammunition with Winchester pistol primers and a magnum ball powder and stuck a bullet in the throat. I replaced that old and tired mainspring with a new one, and that pistol shoots great.

Smith & Wesson K/L/N/X-Frame Mainspring: MGW
At MidwestGunWorks, I suspect the delivered price, using regular USPS shipping, will be closer to $15.

Edit: Nevermind, the OP has already bought one via EBAY.

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432UC/638/642/60 + more

To make the Wolff Power Rib standard power mainspring reliable with hard primers in my 686, I added an Apex extended firing pin, which helped, but wasn't 100%.

I ended up using an extended strain screw that I filed down with a target DA pull of just under 9 lbs. It ended up being 8.6 lbs, and did the trick.

You can straighten out a regular Power Rib spring to work with the normal strain screw. The reduced Power Rib spring is just a regular one with more bend in it. Also, you can bend a mainspring to go around a grip screw, then adjust the strain screw accordingly.

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protocalldesign.com