S&W 686 Misfire Problem

[andersoncouncil]

Hey guys. So I was at the range a couple of days ago, and I had an alarming number of misfires out of my 686. The thing that bugs me is that there were 3 different brands of ammo, and I was able to get all but one of them to fire on a second or third try. I checked some of them before trying them a second time, and the dimples in the primers seemed considerably smaller than usual, which makes it seem like the firing pin is either not traveling the full distance every time or is not striking with enough force.

Any ideas on what my problem could be, and/or how I might fix it?

Also, the one true misfire I had was one of my Remington JHPs, which makes me a little uneasy, since they should be the dependable rounds. Could there be an age factor or something that could help me avoid problems with my defense ammo?

[swifty]

~ The strain screw may be too short, or unscrewed too far.
~ If there is an overtravel stop, it may be adjusted incorrectly.
~ Debris in the action.
~ The mainspring may be too weak or altered incorrectly.

[RickD427]

~ The strain screw may be too short, or unscrewed too far.
~ If there is an overtravel stop, it may be adjusted incorrectly.
~ Debris in the action.
~ The mainspring may be too weak or altered incorrectly.

I'll second all of the above. A lot of S+W revolvers suffer the effects of poorly done trigger jobs. Typically the amateur "smith" will either grind down the tip of the strain screw, or will shave the side of the mainspring, in order to lighten the trigger pull. The consequence of both actions is that the firing pin will strike the primer with less force than it was designed to. A competent gunsmith may be able to lighten the trigger pull, on a target weapon, in this manner, but it is always at the risk of misfire. IMHO, a carry gun should never have the trigger pull modified in this manner. There are many other techniques a smith can use to improve the smoothness of trigger pull in a carry gun.

[scarville]

I has similar problem with my 686. After years of reliable behavior it started having an occasional light strike. At first I thought it was just my reloads but it happened with commercial ammo (Speer Lawman) as well. Even after what I thought was a thorough cleaning, the gun still had the odd frustrating misfire.

Finally after some head scratching, I removed the firing pin and checked the channel in the frame. I could see what looked like gunk (but may have been gunk) against the backside of the bushing. I cleaned it with with a small brush and some solvent, reassembled, and it has worked fine ever since.

I normally clean that channel about once a year whether it needs it or not. Out of curiosity, I checked my reloading logs and ammunition "stockpile". From that I figured it was about 10K or so rounds since it had last been done. Normally I only put 3K to 4K through that gun between the annual deep cleaning but the past year has been busier.

[RedFord150]

If this is your HD gun, I would tell you to send it to S&W or find a qualified gunsmith to get it right. If you have failures on 3 different brands of factory ammo, the issue is probably the gun, not the ammo.
If the gun has been modified in anyway, I would take a hard look at the work that was done.
Good luck.

[littlejake]

Check for powder residue under the ejector star.

Make sure the strain screw is tight. It's not intended as an adjusting screw - it's ground to length.

I've not see a light strike on a 686. Back when S&W introduced the M67 SS model, it had a marvelous double action. After 21 years, the springs weakened enough to make it hit light. It had to go to a gunsmith.

[den888]

Send it to a gunsmith, sounds like light primer strikes.

[shooting4life]

Check strain screw. Also if someone replaced the main spring return it to stock. You might need an extended firing pin but I doubt it unless you are running crushed primers for competition.
I personally believe that when doing an action job on any revolver besides a specific game gun you should not replace any factory springs. A lot can be accomplished by smoothing out any areas metal touches metal inside the action.

[andersoncouncil]

The gun is a little over a year old, it's never been to a smith, and I haven't done any work on it myself. How would I go about cleaning the channel? Does anyone know where I can find a service manual for this model?

[Revoman]

Were you firing in single or double action? I single action, the hammer throw is further and usually stronger because of that. The double action is a shorter throw and usually a little weaker because of that.

BEFORE DOING ANYTHING WITH YOUR GUN MAKE CERTAIN THAT IT IS NOT LOADED!!!!!!!

What others have said should work, it sounds like the main spring tension screw, located at the inside of the grip frame near the bottom, has loosened a little. It's easy to fix. Just remove the stocks (most call them grips) and look for a slot-head screw near the bottom inside of the frame. Simply tighten it up and you should be g2g. This is the most common problem.

If the gun is only about a year old, then it most likely has a captured firing pin, or one that is inside the frame. It could have some build up in there and needs a good cleaning, or the firing pin itself could be damaged.

If you pull back on the cylinder release thumb latch with the cylinder open, you can cock the hammer back and 'fire' it. This should show you how much the firing pin protrudes through the bushing hole, (the hole that the firing pin pushes through to the primer). It should stick out a good bit, at least 1/8" or there abouts. You can also see if it's damaged or broken at that point.

My bet is that it's just the main spring screw loosened up.

[c good]

You didn't mention if you have been shooting any .38 spl through it. If you have then you may need to clean the carbon rings out of the charge holes.

If you put in .357 mag after shooting .38 spl, the carbon rings can keep the magnum round from seating all the way in. When the hammer falls, the firing pin pushes the round down farther into the cylinder taking alot of energy with it. This can cause light primer strikes. If no carbon rings building up....then I agree with other posts. Check the main spring strain screw. HTH c good

[jyo]

I agree, sounds like a mainspring or strain-screw issue---should be easy fix.

[andersoncouncil]

I shoot both .38 and .357, but I clean my cylinder when I'm done shooting and on the day in question I shot only the I shot the .38 last.

The firing pin looks fine, but how would I get in there to give it a "good cleaning?" And how much should I tighten the strain screw?

[Revoman]

"And how much should I tighten the strain screw? "

Tighten the strain screw relatively tight, not like 50 foot pounds, but maybe 15 - 20? You don't wanna break it of course, but it'll take quite a it of torque. Just make sure that the screwdriver tip fits well so you don't bung up the slot, that'll just make it harder to tighten the next time is backs out.

[scarville]

To tighten the strain screw

1. Back it out all the way.
2. Clean the threads
3. Screw it back in all the way using a drop of blue Loctite or equivalent.
4. Tighten it it firmly. No need to torque it down

To clean under the firing pin,

1. Remove it and the small spring
2. clean the hole in the frame with a small brush (or a q-tip?) and some solvent.
3. Dry thoroughly
4. Reassemble.

Some California S&W revolvers have a shortened firing pin which can cause ignition problems. Cylinder and Slide makes a drop in replacement that will extend a few thousandths of an inch further on the strike. About 0.010" IIRC.