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andersoncouncil
05-28-2012, 10:38 PM
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
05-28-2012, 11:43 PM
~ 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
05-29-2012, 12:34 AM
~ 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
05-29-2012, 5:54 AM
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
05-29-2012, 7:41 AM
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
05-29-2012, 7:57 AM
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
05-29-2012, 8:38 AM
Send it to a gunsmith, sounds like light primer strikes.

shooting4life
05-29-2012, 8:38 AM
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
05-29-2012, 4:03 PM
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
05-29-2012, 5:45 PM
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
05-29-2012, 5:54 PM
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
05-29-2012, 6:43 PM
I agree, sounds like a mainspring or strain-screw issue---should be easy fix.

andersoncouncil
05-30-2012, 7:18 PM
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
05-30-2012, 7:56 PM
"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
05-30-2012, 8:26 PM
To tighten the strain screw


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


To clean under the firing pin,


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

c good
05-30-2012, 8:46 PM
Cylinder cleaning is fine but removing the carbon rings from the .38 spl takes some scrubbing. Have you checked the charge holes for carbon fouling?

If they look clean, then, again. I agree on the strain screw idea. If strain screw is all the way in and tight then it's probably a firing pin problem as other's have noted. Always start with the simple things then go from there. HTH c good

orangeusa
05-30-2012, 8:48 PM
Wow.... I never knew that... Serioustalk..... Only had my 686 for 4-5 months...

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

dfletcher
05-31-2012, 8:41 AM
The "mainspring strain screw may have been shortened" comment raises an often overlooked table top tweak. A mainspring strain screw that's been backed out is pretty easy to spot and correct - it sits high, just fully turn in the screw. But some folks, realizing that a standard length strain screw backed out may tend to wander, shortened the length so the result is the same BUT with the screw socked down tight. A quick look for the "backed out" screw will show the screw is fully seated and may cause a person to pronounce it OK and think the problem lies elsewhere. The end of the screw should be flat and straight where it meets the mainspring - I'm sure there's a specific length to the mainspring screw too.

littlejake
05-31-2012, 9:33 AM
"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.

I sure hope you mean inch-pounds. It's not a cylinder head:D

andersoncouncil
05-31-2012, 7:25 PM
So the main spring strain screw should be seated all the way down in the counterbore?

BigDogatPlay
05-31-2012, 7:32 PM
So the main spring strain screw should be seated all the way down in the counterbore?

Yes... as far down as it will go. Don't have to torque it in, but generally speaking the head of the screw should be flush with the frame. If it doesn't go all the way in, check the the counterbore for dirt or debris.

andersoncouncil
05-31-2012, 8:29 PM
Ok. That must have been it. It had backed out by several turns. The trigger pull is considerably heavier now though. Thanks guys.

c good
05-31-2012, 8:58 PM
A little dab of "blue" loctite on the strain screw threads will help this from happening again.

RickD427
05-31-2012, 9:23 PM
Ok. That must have been it. It had backed out by several turns. The trigger pull is considerably heavier now though. Thanks guys.

Glad to see that you got the issue fixed. I've found that heavy trigger pulls can be easily adapted to so long as the trigger pull is smooth. I carried a 6" 686 as my duty weapon for several years. I had a lot of warranty work done on the weapon right out of the box (typical of S+W quality control at the time), fortunately S+W stood behind the warranty and made the weapon quite servicable. The trigger pull was heavy, but very smooth. I'd predicably shoot either 296 or 297 out of 300 each time I qualified. Now with the Beretta 92, I'm shooting all over the 270's and 280's.

andersoncouncil
05-31-2012, 10:22 PM
I'm sure I'll get used to the heavier trigger pull, it's just a little discouraging to have it suddenly change after being used to the lighter pull.

I'd still like to check the firing pin; how do I remove it? I don't see a drift pin. If someone could post detailed instructions on how to remove the firing pin from one of the newer models and/or some drawings that would be much appreciated.