686 Competitor Failure to Fire, part two.

[Zaydok Allen]

Last year I was having some issues with failures to fire with a S&W 686 Competitor, PC gun. After posting a thread here, I was reminded to check the mainspring screw, and make sure it is tightened up properly. Well I did just that, but didn't have a chance to shoot it again. A serious lack of time due to work projects cut into my shooting time, and I had to focus on my defensive guns. All my range sessions were made up of fast shooting and simply focusing on getting rounds on paper as fast as I could. The great part was that I really increased my speed, without much of a loss in accuracy.

The bad part was that the 686 went in a case, and did not get shot until this last holiday season. While at the range I was getting one to three failures to fire per cylinder, in double action. Single action shooting all fired without a hitch. Obviously I found this disturbing as a competition gun is meant to shoot fast. I was shooting Herter's and Fiocchii 158 gr target ammo. The issue occurred with both ammo brands.

Well last night I decided to check the mainspring screw again, figuring it had somehow backed out, and needed a drop of Loctite to be applied. Well, the screw was very snuggly in place and had not backed out at all. So I was puzzled. I couldn't figure out why single action shooting works every time, and double action doesn't.

So I pulled out my 3" 686+ to compare it. The 3" gun has always operated perfectly in single or double action. In comparing the two guns, the hammer locks back at the same distance and angle on both guns in single action. However, in slowly pulling the trigger in double action on both guns, and keeping my thumb on the hammers, I was able to see that the DA trigger break on the 686 Competitor was about 1/8th inch (or maybe even a touch more) shorter than the 3" 686+.

So failure to fire in double action kind of makes sense now, with the trigger on the PC gun breaking a bit sooner than the 686+. I guess I'm looking for some advice from the folks who know S&W revolvers. I haven't taken the side plate off, as I am concerned about clumsiness on my part leading to lost springs, or gouged up screws and finish.

It seems to me that I would get one failure to fire occasionally in a range session in the past, and now the problem is worse. So it seems to me that the mainspring is not the issue, but rather it is an improperly cast or milled part in the hammer and/or sear mechanisms? I may be way off so please chime in.

I guess I'd like advice from the experienced folks too about whether I should go on an exploratory mission, or simply contact S&W. I hate sending my guns in, but I hate screwing up things that I paid a lot of money for even worse. I'm not terribly mechanically inclined and don't have a good work space with proper lighting to do much service work on a gun, so I'm really reluctant to go digging around.

What say you?

 

[MrBorland]

I'll take a whack:

The shorter hammer fall sure seems like a likely culprit, but may or may not be the underlying problem, as another may be excessive energy-robbing friction between the hammer and frame, or within the firing pin travel. Or it could be a combination of any or all of these things.

If you're reluctant to go digging around, I'd ask a local gunsmith for their take. If hammer-travel is purely the issue, it might require a trip back to S&W. If either the hammer sear or trigger cam (see labels & pic 4 below) is too short (causing short travel), the part would need to be placed anyway, so it'd be best to have it done on S&W's dime.

 

[Zaydok Allen]

Thanks for the response Mr. Borland. It sounds like I'm on the right track though lacking technical know how. Based on the photo you included (which is great by the way), I see what you are saying. If the DA sear, trigger nose, or cam are too short, the hammer will fall prematurely, and impact with less force than needed in DA shooting. This problem would not occur in SA firing mode.

This more or less confirms my suspicions. I think I'm probably just going to contact S&W about it. They sold me the gun and should fix the problem.

I would think if there was friction causing a loss of power in the hammer fall, that the issue would get better the more I shot the gun, as rubbing metal would polish itself down over time. No?

I'm going to wait for some of the other experienced folks to chime in as well, but I think this answers my question. It isn't something I'm going to fix myself.

 

[Master Blaster]

Does your 3" 686 have a standard full power spring?

The PC probably came with a reduced power bossed mainspring like my pc 627. A standard spring may fix your issues. Otherwise send it in to S&W.

 

[Zaydok Allen]

Hmmm. It looks normal to me on the PC gun, but when pulling the trigger, it feels light. It may just feel that way though because the action is really smooth. I also wondered it the strain screw is too short. If either of those were the culprit though, wouldn't single action shooting be a problem as well?

I'll double check that tonight. The 3" does have a standard spring from what I can tell.

 

[MrBorland]

If the DA sear, trigger nose, or cam are too short, the hammer will fall prematurely, and impact with less force than needed in DA shooting. This problem would not occur in SA firing mode.

This more or less confirms my suspicions. I think I'm probably just going to contact S&W about it. They sold me the gun and should fix the problem.

I would think if there was friction causing a loss of power in the hammer fall, that the issue would get better the more I shot the gun, as rubbing metal would polish itself down over time. No?

Just to clarify - it might be the trigger travel, or it might be something else, like internal friction. If the latter, I doubt that it'll get better with shooting. Shooting will burnish or polish some surfaces, but won't remove enough metal to relieve the resistance. On the bright side, if it is a resistance issue, it's something that can your local gunsmith can probably fix.

As mentioned, it could be the spring tension, but it still ought to be reliable from the factory.

I do agree that it's best to contact S&W.

 

[243winxb]

A test for a Smith and Wesson revolver, model 28, 357mag., may work on other guns also<> Gun empty.
Dryfire gun and hold trigger fully to rear.
Cock hammer with thumb.
Hook a weight around the hammer (for example 3 1/2 LB minimum weight for 357).
The hammer must not move rearward when the gun is lifted.
The hammer should lift 3 1/2 lbs without going into the cocked position.

 

[Zaydok Allen]

Just to clarify - it might be the trigger travel, or it might be something else, like internal friction. If the latter, I doubt that it'll get better with shooting. Shooting will burnish or polish some surfaces, but won't remove enough metal to relieve the resistance. On the bright side, if it is a resistance issue, it's something that can your local gunsmith can probably fix.

As mentioned, it could be the spring tension, but it still ought to be reliable from the factory.

Gotcha. Thanks again.

 

[strambo]

It could be the PC version uses a shortened mainspring screw? When my wife's came back from a trigger job it had an amazing DA pull, but we would get light strikes once in a while. I saw the screw had been shortened by the smith and I just swapped it out with a stock replacement, it noticeably improved the power of the hammer drop and only increased the DA pull a little bit, still light and super smooth.

It will be interesting to hear what S&W says, but comparing your mainspring screw to your other S&W might tell you something.

 

[Zaydok Allen]

It will be interesting to hear what S&W says, but comparing your mainspring screw to your other S&W might tell you something.

That's a great idea also, and will look at it when I compare the mainsprings tonight. I'm realizing I'm quite fortunate to have a second 686 to compare it to. It still seems odd though that the hammer on the PC gun doesn't travel as far back as on the 3" 686 in DA. I don't think a different length strain screw would cause that would it? That's got to be a difference in trigger mechanism and hammer parts from one gun to the next.

 

[Zaydok Allen]

Does your 3" 686 have a standard full power spring?

The PC probably came with a reduced power bossed mainspring like my pc 627. A standard spring may fix your issues. Otherwise send it in to S&W.

The mainspring screw is the same length on both guns.

The mainspring on the 3" 686 is a standard spring. The spring on the PC gun is in fact a bossed mainspring, as you suggested.

 

[pintler]

There are other possibilities, as well. I once returned a new 629 to Smith for repair for insufficient firing pin protrusion, for example. It had the same symptoms - occasional failure to fire.

If Smith sold you a model with reduced power springs (to get a better trigger pull), I think it's their job to get the system to work, rather than you having to put in stiffer springs and get an ordinary trigger pull.

FWIW, I've had good luck with factory service. My sense is that it's not uncommon for them to go beyond just fixing the immediate problem. You might end up with a really nice trigger. Of course, some people have bad luck and you hear the occasional horror story, so YMMV. But I'd just send it back, and hope the guy who gets assigned to work on it is having a slow day and can go the extra mile.

 

[Zaydok Allen]

To clarify, I will be contacting S&W. The gun is called a "Competitor" and won't fire reliably in DA. That's like selling me a sports car that you can only drive in first gear, and S&W needs to make it right.

I thought about going looking, but there is no need on my part. I am the original owner, so warranty work shouldn't be a question, and the malfunction is something that needs to be looked at by a professional, not by me looking at mechanisms and guessing what the problem is.

I'll update with info when I hear from S&W. I'm more curious than anything to know what the issue is that's causing the problem.

 

[243winxb]

Bossed Mainspring.

Wolff U.S. Patent No. 4,693,027. http://www.gunsprings.com/index.cfm?page=items&cID=3&mID=58 I learned years ago to avoid Wolff Springs. Just a refresher course to jog my memory. Could S&W have copied it?

 

[Zaydok Allen]

No idea. It looks similar though.

 

[HankB]

Friend of mine had a similar problem - he fixed it by putting a spent primer over the end of the strain screw that contacts the mainspring, effectively lengthening the screw. Worked for him, and easy enough to try.

If not, then I'd guess the culprit is the fitting between the DA sear and the trigger nose - which is a little more difficult to rectify. (Maybe someone stoned the surfaces with a little too much enthusiasm.) It may need a new sear and/or trigger. With the fitting required, either the factory or a good revolversmith should be able to fix it.

 

[Zaydok Allen]

HankB,

It seems strange that the hammer on the PC gun drops noticeably earlier and while closer to the firing pin than on the other 686. If the reduced power spring or the strain screw were the only problem, I would think the hammer would travel nearly as far back on both guns. Right? Or am I wrong there? The shorter travel of the hammer may not even be the cause I realize. I'm just trying to enhance my understanding of the internal workings of S&W revolvers.

I think you are correct about one of the surfaces being stoned a little over zealously.

 

[MrBorland]

I'd guess the culprit is the fitting between the DA sear and the trigger nose - which is a little more difficult to rectify. (Maybe someone stoned the surfaces with a little too much enthusiasm.) It may need a new sear and/or trigger.

One one hand, I think it's unlikely to be the DA sear/trigger nose. If you look back at pic #4, you'll see the trigger nose does indeed engage the DA sear, but this engagement transitions to a 2nd engagement between the hammer sear and trigger cam. What you don't see in the picture is that as the trigger's pulled further, engagement is fully between the hammer and trigger cam. IOW, the DA sear and trigger nose are no longer even engaged when the DA shot breaks.

OTOH, I suppose it's possible that the DA sear is SO short the cam's not even engaging, in which case the DA trigger would break really early. But hey, maybe that is what's happening. If so, the fix is simply to fit a new DA sear. That's something a local gunsmith can do. Or heck, it's not really all that hard to do at home if you've got patience and a good stone. If you're the curious sort, maybe pop the sideplate (back off the strain screw a bit first), and confirm the hammer breaks off the cam, and not off the sear/nose engagement.

It seems strange that the hammer on the PC gun drops noticeably earlier and while closer to the firing pin than on the other 686. If the reduced power spring or the strain screw were the only problem, I would think the hammer would travel nearly as far back on both guns. Right? Or am I wrong there?

Well, I'll go out on another limb and say "who knows?": Unlikely as it is, perhaps S&W decided that since it's labeled as the "Competitor" 686, it'll be engineered for an early DA break, thinking it'd be faster to shoot. This is partly why I was suggesting it could be something else.

 

[Zaydok Allen]

One one hand, I think it's unlikely to be the DA sear/trigger nose. If you look back at pic #4, you'll see the trigger nose does indeed engage the DA sear, but this engagement transitions to a 2nd engagement between the hammer sear and trigger cam. What you don't see in the picture is that as the trigger's pulled further, engagement is fully between the hammer and trigger cam. IOW, the DA sear and trigger nose are no longer even engaged when the DA shot breaks.

Based on what you have shared and described MrBorland, and how the hammer moves on the gun, I think you are right. I doubt the DA sear/trigger nose engagement is the problem. If that was the issue then as you say here,

I suppose it's possible that the DA sear is SO short the cam's not even engaging, in which case the DA trigger would break really early. But hey, maybe that is what's happening.

would be taking place. The hammer would fall much earlier than intended, as the initial engagement ends prematurely. That is not happening. As I said earlier, with the 3" 686 I compared it to, the hammer falls when about 1/8th of an inch further back than on the PC gun, though, maybe that is a lot. So, just trying to think it out, it seems like the point where the trigger cam is engaged with the bottom of the SA sear is where the slip is occurring. To heavy of a stoning on either or both surface might cause it, correct? Assuming that is where the issue is. As you said, it may be something else.

Now I'm getting really curious and kind of want to open her up to see what it looks like.

 

[Jim K]

If the trigger is breaking off the DA sear, it is easy to check without even removing the sideplate. Take a piece of wood or plastic thick enough to be stiff, and thin enough to fit down in front of the hammer (a split popsicle stick will work fine). Using the DA mode, pull the trigger until the hammer is back part way, put the "tool" down in front of the hammer and push back against the DA sear. If it moves, it is disengaged and the trigger is on the lower hammer cam. Try this at different hammer positions. If the hammer is about at the release point and the DA sear won't move, things are not right.

I suspect that is not the problem, though. I would try inserting something, like the fired primer without the anvil that Hank B suggests, between the strain screw and the spring and see what happens.

Jim

 

[CopperFouling]

I had some light strikes with a 686. They only occurred in DA. Somehow, the strain screw had backed out a little. Tightening that solved my problem.

 

[Zaydok Allen]

The strain screw is fully tightened. That isn't the problem.

 

[Zaydok Allen]

Dropped her at FedEx a few hours ago. I'll update when I hear something. I'm interested to hear what the issue is.

 

[Old Fuff]

Over a period of many years I have learned that when something goes wrong the tendency is to look for a single cause (such as a weak mainspring) and have it turn out that several conditions combined was the source of the issue. They were overlooked because the entire focus was toward finding a single solution.

In my view you made the right decision to send the revolver back to S&W when it became clear that the cause apparently remained undiscovered.

It's their baby, so let them fix it.

 

[Zaydok Allen]

Yup. Their product, their service policy, their reputation to uphold. I'm sure it'll turn out ok. I kind of expected more from the performance center though. But hey, stuff happens. I'm just excited to have it fixed. I really enjoy that gun.