S&W K frame Spring Kit

[88E30M50]

Does anyone have any experience with the Wilson K Frame spring kit for a Smith and Wesson revolver? I installed one last week and initially went to the 12# spring, but was getting light strikes. I skipped the 13# and moved to the 14# spring and am still getting light strikes. I replaced the Wilson leaf spring with the factory spring and all is fine again. The trigger is heavier, but with the Wilson trigger springs, it still feels better than before.

Has anyone else run into light strikes when using the Wilson hammer leaf spring? If so, is there any trick to installation that I may have missed? I installed it without any issues and tightened the spring screw down until it bottomed out. Could that screw be short maybe? I'm wondering if the screw was shortened, it may not be applying enough tension to the hammer, but that's a WAG at best.

Thoughts?

 

[Hopper]

Does anyone have any experience with the Wilson K Frame spring kit for a Smith and Wesson revolver? I installed one last week and initially went to the 12# spring, but was getting light strikes. I skipped the 13# and moved to the 14# spring and am still getting light strikes. I replaced the Wilson leaf spring with the factory spring and all is fine again. The trigger is heavier, but with the Wilson trigger springs, it still feels better than before.

Has anyone else run into light strikes when using the Wilson hammer leaf spring? If so, is there any trick to installation that I may have missed? I installed it without any issues and tightened the spring screw down until it bottomed out. Could that screw be short maybe? I'm wondering if the screw was shortened, it may not be applying enough tension to the hammer, but that's a WAG at best.

Thoughts?

YES, I have experience with the Wilson Combat spring kits. They work brilliantly in my NM 66 Combat (the new model introduced last year). I used the WC main spring and the 13# trigger return spring, and it's been nothing but butter in SA and DA across various brands of 38 and 357.

However... using this same setup in a recently purchased 686 3" resulted in exactly the same behavior you are experiencing. No problems in SA, but random light primer hits in DA. Unfortunately, I had to go back to the stock setup in the 686, and will need the trigger to get better the old-fashioned way... by shooting it in.

Also, the trigger return spring you install in that little black rebound slide, that won't make any difference in DA light primer strikes. That spring affects how quickly your trigger returns to the starting line after you squeeze it, and changing between the various springs will NOT overcome the main spring being too light for your gun.

While it's possible the original strain screw could be a bit short (they can sometimes "mushroom" out at the bottom, requiring a longer replacement), I suspect it's really that the main spring is just too light. You definitely need that strain screw installed all the way. I will put a dab of Blue Loctite on mine to make sure it doesn't back out.

Sorry for the mediocre news, but hopefully this helps.

**Edit** - are you installing this in that 66 of yours? If so, you COULD try an extended firing pin. My 686 is a newer model with the regular length firing pin, but depending on your dash, it could be that you have one of S&W's shorter firing pins they used for a while as a safety precaution when they went to that "transfer bar" setup with the floating firing pin. That's an easy install, too.

Cylinder & Slide Extra Length Firing Pin New-Style S&W J K L N-Frame

 

[88E30M50]

It does help. I was wondering how the trigger return spring could impact the hammer, but recall seeing instructions somewhere that said to install the lightest spring and then go heavier if light strikes happen. I may have heard that wrong or the poster may have stated it wrong. It does suck that it's not working as hoped. The DA trigger on the old 66 felt pretty darn nice with it in there.

 

[Hopper]

FWIW, there's a member on here in Southern IN that I've thought about hitting up to sweeten my 686, because even with the 3" barrel and heavier factory setup, it's lights-out accurate. His handle name is "Bosshoss", and he's down around the Jasper area. I've hit him up on PM with a previous revolver question/issue, and he was quite helpful. He is the llh1956 of revolver wizardry.

Also, I think the geometry of your 66, and my newer 686, are enough different from the NM 66 Combat to make that WC main spring not behave as well as it could. Even in my younger brother's NM 69 Combat, the WC upgrades produced amazing results.

And yes, I felt your pain... pulling those parts out of my 686 and going back to the heavy factory setup was a complete bummer.

 

[T755]

The strain screw could be short. This is why in a lot of older guns you will find them shimmed, usually with a large pistol primer cup. The factory rate spring is the hammer stationary holding a 3.5 pound load for a magnum. This is normally checked with a trigger weight hanging just under the hammer nose with the barrel pointed up. Wolf and wilson both are not quite enough without shimming or fitting a new strain screw with is preferred. New strain screws are still fairly easy to obtain and fit.

 

[88E30M50]

The strain screw could be short. This is why in a lot of older guns you will find them shimmed, usually with a large pistol primer cup. The factory rate spring is the hammer stationary holding a 3.5 pound load for a magnum. This is normally checked with a trigger weight hanging just under the hammer nose with the barrel pointed up. Wolf and wilson both are not quite enough without shimming or fitting a new strain screw with is preferred. New strain screws are still fairly easy to obtain and fit.

That's really good info to hear. I think I'll give the shim idea a try and if it pans out, will start the search for a longer strain screw. Lord knows, I have enough large pistol primers floating around to try it with.

 

[Drail]

OP, are you getting light hits with all brands of primers? Will it set off CCI primers? Will it set off Federal or Winchester primers? Does your S&W use a frame mounted firing pin or hammer mounted? Light hits have been an issue ever since S&W went to the frame mounted firing pin. The fix for those guns is a longer firing pin. I have been using the Wilson S&W spring kits for over 25 years on the old style S&W revolvers and have never seen a Wilson mainspring cause a failure to fire. The only reason you will ever see a shimmed strain screw is because someone cut it too short. That is not a spring problem.

 

[Hopper]

Drail, you've convinced me to give this one more go with an extended firing pin. The factory springs are OK in SA, but pretty heavy in DA. I just ordered the extended firing pin, and will report back once I give my 686+ a run at the local range.

 

[Bosshoss]

The Wilson and Wolff spring kits are designed to work with a full length strain screw.
The rebound spring has nothing to do with the light strikes.
Shorting the strain screw is a common way of lighting the trigger pull. It is ok if you know what you are doing. Taking too much off the strain screw can cause the mainspring to make contact with the hammer which is call knuckling. Shorting the strain screw can also cause problems with grips that have a screw that goes in from the side. With the shorter strain screw the grip screw can hit the mainspring.
The rebound spring must be "balanced" to the mainspring for a positive trigger return.
Several things can cause light strikes in a S&W revolver.
Besides mainspring tension some of the more common ones are hammer drag and excessive cylinder endplay(even on new guns). Dirt under the extractor star or a really dirty cylinder can be a problem.
The firing pins usually are not a problem until you get into really light double action pulls.
S&W did make some guns with really short pins to pass the California drop test.
S&W also made some really good pins.
Measure your firing pin.
The really short pins that should be replaced are around .475-.480 long.
I would also replace the ones the are under .485 although those are rare.
Most run .485-.492 and are Titanium these are good for general shooting and carry.
Some factory pins are .495-.497 and are Titanium these are great and I will buy these off of you.
The aftermarket pins are all steel,
Apex pins are .495 and a good pin very durable.
Power custom pins are .505 and hold up very well.(this is what I put in the competition guns I build)
Cylinder and slide pins are .510 and good pins. Somewhat fragile compared to the others if you dry fire a lot but still a good pin.
IMO extended pins don't make much difference until you start getting under 7.5 pounds DA.
They don't hurt anything other than being more fragile.
FWIW I use Wolff rebound springs and the stock S&W mainspring(that I alter) in all my action jobs.

 

[Hopper]

Excellent info ^^^ Bosshoss, thank you for posting this!

 

[Hopper]

Drail, you've convinced me to give this one more go with an extended firing pin. The factory springs are OK in SA, but pretty heavy in DA. I just ordered the extended firing pin, and will report back once I give my 686+ a run at the local range.

Reporting back, as promised. I re-installed the Wilson Combat spring kit in my 686 Plus 3", this time with the 14# trigger return spring, and the "Cylinder and Slide" extended firing pin. It was a no-go, still too many light primer strikes. I stopped after running a second cylinder of ammo, and returned it back to factory settings.

With my younger brother living down in the southern part of the state, I may schedule a dr's appt with Bosshoss to see what kind of trigger surgery magic he could do.

 

[88E30M50]

OP, are you getting light hits with all brands of primers? Will it set off CCI primers? Will it set off Federal or Winchester primers? Does your S&W use a frame mounted firing pin or hammer mounted? Light hits have been an issue ever since S&W went to the frame mounted firing pin. The fix for those guns is a longer firing pin. I have been using the Wilson S&W spring kits for over 25 years on the old style S&W revolvers and have never seen a Wilson mainspring cause a failure to fire. The only reason you will ever see a shimmed strain screw is because someone cut it too short. That is not a spring problem.

This is a 66-2 and has the hammer mounted firing pin. Since going back to the stock spring, I've had no issues. I still need to order the new strain screw, if for no other reason than to compare a new one to the one that's in there. I bought this gun used and who knows if the screw was shortened in the past.

 

[bgcatty]

Does anyone have any experience with the Wilson K Frame spring kit for a Smith and Wesson revolver? I installed one last week and initially went to the 12# spring, but was getting light strikes. I skipped the 13# and moved to the 14# spring and am still getting light strikes. I replaced the Wilson leaf spring with the factory spring and all is fine again. The trigger is heavier, but with the Wilson trigger springs, it still feels better than before.

Has anyone else run into light strikes when using the Wilson hammer leaf spring? If so, is there any trick to installation that I may have missed? I installed it without any issues and tightened the spring screw down until it bottomed out. Could that screw be short maybe? I'm wondering if the screw was shortened, it may not be applying enough tension to the hammer, but that's a WAG at best.

Thoughts?

Why waste time and money messing around with springs and screws??? Take your money, find a good S&W gunsmith and get a complete action job and be done with it! You will be way ahead and not deal with self made frustrations. One such gunsmith is Denny Reichard at Sand Burr Gun Ranch in Rochester, IN. You won't be sorry!

 

[88E30M50]

That's not a bad idea. I used to have a nickel 586-1 that had a trigger that was almost telepathic. You just thought 'break' and it did.

 

[Skyhawk]

This is a 66-2 and has the hammer mounted firing pin. Since going back to the stock spring, I've had no issues. I still need to order the new strain screw, if for no other reason than to compare a new one to the one that's in there. I bought this gun used and who knows if the screw was shortened in the past.

You're on the right track. If the new mainspring tension screw doesn't solve the problem then go to a gunsmith. I'm a gunsmith and S&W are one of my favourites to work on. They aren't complicated like some and when in tune work smoothly and reliably. good luck

 

[88E30M50]

I need to turn this one over to a gunsmith. I got the new strain screw today and it's .090 shorter than the one that was installed. With the Wilson mainspring installed, the new screw does not even touch it when screwed in all the way. I've got a couple of other projects in the works, but once those are cleared off the bench, I'll start looking for a good revolver smith to make this puppy sing.

Here's the Wilson K frame spring that came in the kit:


Here's the new screw:


Here's the Wilson spring with the new screw tighted down completely:

 

[Thor]

88E30M50 - what was your outcome? I am currently working on a N frame that has light strikes in DA, ordered a replacement strain screw from Numrich and it's the same length as the one that is in the pistol so it was probably not modified and I'm not expecting a different outcome at the range. I ordered the extended firing pin from Cylinder and Slide and talked to Wolff Springs, they said they have an extended strain screw to help in these situations.

There's a lot that seems to be wrong in your photos above, both the mainsprings and strain screws are different. Hope it's a functioning weapon now.

Cheers

 

[walt o]

Did you get a strain screw for a round butt.The top screw in the picture has definitely been screwed with S&w strain screws are domed like the bottom screw,not flat like the top screw . Use the old screw but slip a used primer over the tip (remove the anvil from the used primer) that usually allowed more tension on the main spring . and you can test fire it to see if it helps .

 

[88E30M50]

I ended up just restoring the original springs, with the intention of sourcing a longer screw at some point. It's been a while since that one has been out of the safe and I really need to revisit the project. I did try the primer cup back when I was working on the gun and it did seem to solve the issue, so I think that the longer spring will make it right again with the new spring package. Thanks for the tip on where to look for the longer strain screw. I'll check that out today.

 

[Thor]

Tech support at Gunsprings dot com (Wolff) recommended calling them to order, 800-545-0077.

I had contacted them because they didn't specifically state that they made springs for my model but they do.