S&W J frame mainspring question.

[km101]

Recently bought a model 60 and the DA trigger pull is very heavy. The standard weight mainspring is supposed to be 8.5#. The only replacement spring I can find is 8# from both Wolff & Wilson Combat. Is this supposed to be the minimum weight for reliability? Seems to be an industry standard, but has anyone tried anything lighter?

I don't want to just start chopping springs and replacing because they are a pain to replace. Any information? Anyone tried this with good results? Any help/information appreciated.

 

[OKFC05]

Lots of people have clipped the coil springs, and many have discovered the truth that the J frames don't tolerate light springs as much as the old K's. Suggest you try some deburr, polishing, and the somewhat lighter spring. Smooth feels lighter.
J springs are easy to replace using a homemade paperclip tool.

 

[hkcavalier]

I went with the Apex Duty kit. Somewhat sharper firing pin, smoother springs. I believe the pin return spring is lighter, but not the other springs. It's been flawless in my 442. The difference was not dramatic, but was/is noticeable (in a positive way).

 

[AJR337]

Wilson has a package that contains an 8# hammer spring and 13, 14, 15# rebound springs (I believe that the factory weight is 18#).

I installed the 8# hammer spring along with the 14# rebound spring in my 640 and polished the rebound slide contact surfaces.

The trigger pull is very smooth and consistent with no stacking.

 

[scooter123]

I recently acquired a model 36 circa 1958 that is in what appears to be unfired condition except for the factory testing. Trigger pull was at a level I can only estimate because my Lyman Digital Trigger gage overloaded BEFORE ANYTHING MOVED. BTW, the overload point on this gage is 12.5 lbs. As for my estimate, I would say it was in the 14 to 17 lbs. range and that was with the Rebound spring already changed to a 13 lbs. rebound spring.

The solution for me was to order in that Wolff 8 lbs. mainspring. By with that 13 lbs. Rebound Spring and the 8 lbs. Mainspring the trigger now tests at 9.90 to 10.1 lbs.. Cannot address how reliable it is beyond stating that in one empty case with a fresh primer it did fire. Bad news is that primer backed out of the pocket and tied up the action pretty darned tight. Once I figured out what was going on a bit of very firm thumb pressure at the rear of the cylinder allowed me to open up the revolver. One of these days I'll take a break from shooting Trap and Skeet and get in some quality time with the model 36 and see how it performs.

PS: the mainspring that was in the model 36 from the factory appeared to be a much more robust spring than the Wolff Spring. The wire was 0.004 inch thicker and it appeared that the coils were spaced a bit closer together. At a guess I would think that it's probably a 9 to 11 lbs. spring. Which may explain the drastic drop in trigger weight when the Wolff spring was installed.

 

[ImprovedModel56Fan]

I don't really know much of anything about J frame revolvers, which is to say that I don't know factory spring weights then and now, and don't actually know whether the factory-supplied springs have changed over time or not.

I do have a bit of experience with J frames, and I will tell you what little I think I know.

My first J frame was a Model 40. I spent a lot of time dry-firing it, and I lubed it. I never changed springs. As you might suspect, all of my dry-firing was DA.

I eventually learned that RIG +P Stainless Steel Lube was in a class pretty much by itself (sui generis for the Latin students). I believe that polishing a rebound slide with a hard Arkansas stone is a good thing, as is use of abovementioned RIG +P SS.

Austin Behlert smoothed up a 37 (and other revolvers) for me. I can not tell you all that he did, because I do not know. I do know that he altered the mainspring. I also know that the revolver still worked reliably with all ammo.

In K-frame revolvers, I have had problems with reducing the force of the rebound-slide spring.

In my opinion, based on limited knowledge and some experience, good results will come from polishing the rebound slide and using the abovementioned grease sparingly throughout the action of a J-frame revolver. Mainspring weight can be reduced if tested for reliabilty of ignition. While some people can reduce rebound-slide-spring weight without detriment to reliability, I'm pretty sure that I cannot.

That's about all I know.

Best wishes.

 

[Hondo44]

J springs are easy to replace using a homemade paperclip tool.

But taking off and reinstalling the new spring onto the strut is the problem.

Here's a few methods for installing the spring on the spring strut for Ruger coil springs that are adaptable to S&W hammer springs:

Rugers-spring.html

 

[Hondo44]

Bad news is that primer backed out of the pocket and tied up the action pretty darned tight. Once I figured out what was going on a bit of very firm thumb pressure at the rear of the cylinder allowed me to open up the revolver. One of these days I'll take a break from shooting Trap and Skeet and get in some quality time with the model 36 and see how it performs.

Primers always back out on each shot. However, w/o the powder charge to slam the case back and reseat the primer, you'll get the hangup. If you drill out the case flash hole to about 3/32" (not a critical size), the primer will not back out. I keep six cases on hand in each caliber I shoot, that I've drilled out just for testing ignition.

 

[WR Moore]

You might also try a different factory weight spring. Every great once in awhile, you get a spring that's, for some unknown reason, way out of spec. You might also deburr the hammer strut.

J frames have a very narrow range of mainspring weight to remain reliable. This is, in large part due to the light hammer and the reduced mechanical advantage the spring has. As a result, I kept the factory springs with a bit of burnishing of the strut.

Check carefully for wear marks that might show mechanical interference.

BTW, in the case of a cylinder locked by an extruded primer, a brass rod inserted down the barrel and tapped lightly will push the primer back in the pocket.

 

[white cloud]

This has been and interesting and very useful thread.

 

[km101]

Thanks gentlemen for the information and advice! You have been most helpful and I appreciate it!

I will order the Wolff spring kit as I have had good results with their products in the past. With new springs and some careful polishing I hope to have a much better trigger.

As said by white cloud "This has been an interesting and very useful thread." Thanks again!

 

[Mzuri]

I have a related question. I have a pre-40 Centennial that has an amazingly light and smooth trigger. It also has chronic light strikes. I think the reason the trigger is so light may have to do with the main spring having been changed or modified at some point in the last 65 years. I want to replace it with a stock spring but the Wolf and Wilson spring packs from Midway all have a long list of J-frame models they are compatible with, but the 40 and the pre-40 are not on the list. My assumption is that what works on one J-frame will work on them all, but I also know that 40s need different grips so I might be mistaken about this. Will a standard J-frame spring work in an old pre-40?

 

[Bobafett]

The only time I ever tried a lighter mainspring in a j-frame was a 317, I believe factory weight was 12lb so I used a wolff .22 j-frame spring kit and found I now have an unreliable .22 j-frame.

In fairness, it failed in DA pull but not SA pull with the lighter hammer spring.

I wouldn't tempt fate with a personal defense weapon.

Go with a lighter rebound spring to lessen the trigger pull.

 

[steelslaver]

To load coil springs on the strut.
Get a piece of 1/4" pipe from the hardware store and a T. Screw the lateral opening of the T on the pipe. Use a Dremel grinder to make a slot in the other end of the pipe. Take a piece of hard wood and start a shallow 1/4 hole in it. Lay down the wood. stick the ball end of strut in it, stick on spring use pipe tool to compress and install a pin via the slot.

I got all kinds of interesting tools in my gun tool drawer.

 

[StrawHat]

If you can, please post a photo of that tool.

My minds eye needs a new prescription.

Kevin