686 malfunction

[Mike_Fontenot]

At the range this morning, my 686 malfunctioned. When the hammer was down, the cylinder was locked in place as it should be. But when the hammer was cocked, the cylinder would rotate during the cocking as it should, but the cylinder wouldn't lock into place as it should once the cocking was complete ... after cocking, the cylinder could be freely rotated by hand (in the same direction of rotation as during the cocking). This happen consistently and repeatedly at the range, so I KNOW that there are one or more internal parts that are broken, worn, damaged, or out of spec. When I inspected the live round that didn't fire when it should have, there were marks from the impact of the firing pin on the rear of the case, most slightly outside of the primer, but one just inside the rim of the primer. Fortunately it didn't ever fire.

I decided to clean the gun before I sent it in, because I didn't know how long it might sit around before I got it back. But after I did that cleaning, I can no longer reproduce the problem.

I called S&W back (they had earlier given me an RMA to send it back), and told them that after cleaning I could no longer reproduce the problem. They assured me that they would not just return it to me as "no trouble found", so I've just Fed-Exed it back.

Any ideas on what's wrong?

 

[oldiesradio1560]

I brought a 686-1 used from LGS back in the 90's developed that lock problem about two weeks after purchase. LGS ordered a brand new one for me. No problem with the new one.

 

[H Richard]

It's very possible that an accumulation of shooting residue (crud) internally kept your latch from rising up and engaging the notch as it should. Possibly cleaning it got just enough cleaner into the hole and loosened up the residue and allowed it to become free. If not totally cleaned out it might happen again. Probably just a total tear down and cleaning inside will fix the problem.

 

[Mike_Fontenot]

It's very possible that an accumulation of shooting residue (crud) internally kept your latch from rising up and engaging the notch as it should. [...]

But every time I lowered the hammer, the latch would rise up every time and lock the cylinder as it should.

Hammer down -> cylinder locked;
Hammer cocked -> cylinder not locked.

 

[Ashlander]

Mike: If you're comfortable taking the side plate off and slowly cycling the action, you can see a lot of what's going on and not going on (if you get my drift). Just keep the rebound slide pushed in with your finger (they don't call it a slide for nothing). After a few trigger pulls it wants to work its way out of the gun.

 

[Mike_Fontenot]

Mike: If you're comfortable taking the side plate off and slowly cycling the action, you can see a lot of what's going on and not going on (if you get my drift). Just keep the rebound slide pushed in with your finger (they don't call it a slide for nothing). After a few trigger pulls it wants to work its way out of the gun.

Thanks for that warning about keeping the rebound slide in place. The gun is on its way back to S&W. Hopefully they can diagnose and fix the problem even though it's not been reproducible ever since I cleaned it.

 

[Bob L]

IT could also be that you had a build-up of crud under the star extractor. I have had that before and if it doesn't retract all the way, it will not lock up and you can spin the cylinder.

 

[JDinAZ]

Sure sounds like you had a dirty or sticking cylinder stop. If it doesn't engage you will experience cylinder free roll in the same direction as normal cycle. From your description the pawl seems to function fine since the cylinder didn't roll backwards. You probably fixed it on your own by cleaning it.

 

[johns961]

I had kind of the same problem a couple years ago with a semi new seldom fired 686. I suspected the hand was bad. I sent it back to Smith.
A week later I got it back from them. They replaced the hand and the rest of the mim parts. Been good ever since.

John!

 

[Mike_Fontenot]

I've had it back from S&W for a couple of months. The only thing they said they replaced was the "trigger pin". Since then, I've had one failure-to-lock after a cock, after at least a couple of hundred cocks. This time, it didn't stay unlocked ... I lowered the hammer, cocked it again, and it locked OK. I've probably cocked it a couple of hundred times since then, and checked for locking after each cock, with no more failures. If it happens again, I'm going to try, before I do anything else, to see if the trigger is fully forward ... I've got the lightest possible trigger rebound spring in that gun (11 lbs, I think).