Model 66 no dash Cylinder lockup

jcfoxcroft

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Hello. I have a Model 66 no dash pinned 2-1/2 barrel.
Intermittently, when the trigger is pulled or the hammer is pulled back the cylinder locks up. The trigger or hammer only moves back slightly (maybe 3/16") and the cylinder doesn't revolver at all. Releasing the pressure on either the trigger or hammer and allowing them to fall back to rest and retrying the action again normally allows the gun to work for the follow up.
I 've taken it apart and examined all parts under a magnifying glass.
Does anyone have any suggestions?
Greatly appreciated.
 
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Does this happen after firing it some previously ? Originally, the Mod 66 was recalled for cylinder lock up, my vague memory tells me it had something to do with the early alloy of Stainless being used, causing it to heat up and expand causing it to bind. If this is the case it may be covered under the recall.
 
OK. Thanks for the input. The gun is absolutely clean and I haven't noticed and burrs or such to impede movement. When I view the gun sideways and dry fire it I can see the cylinder stop drop below the frame but occasionally the cylinder just doesn't rotate and it locks up. So I will concentrate on the hand movements. I can remove the side plate and observe the movements.
Thanks. I'll keep you posted.
 
The first issued duty revolvers by my department back in the 70's were model 66-0. Before that we bought our own. We went to the range for familiarization on our new duty guns. 30 officers lined up on 30 targets and at least 15 of the 66's locked up similar to what you are describing. All 60 guns from that order went back to Smith for modifications. I don't remember what the problem was but they worked fine when they came back and we carried them for several years. The same thing happened after we switched over to the new "L" frame 686. By then we had a S&W trained armorer and he fixed the problem and we carried those for a few years and it's been Glocks ever since.
 
S&W revolvers like yours are intricate pieces of machinery. If they left the factory working flawlessly they likely will continue to do so with reasonable cleaning. Too much lubrication, especially of products that gum with time, will cause them to cease working. If someone who really does not understand them has been inside the lockworks it can be cause for nonfunctionality.

I've seen a few that got pushed out of the factory before they were ready. Most can be made to run like a S&W should; a couple should have been scrapped at the factory.
 
The first issued duty revolvers by my department back in the 70's were model 66-0. Before that we bought our own. We went to the range for familiarization on our new duty guns. 30 officers lined up on 30 targets and at least 15 of the 66's locked up similar to what you are describing. All 60 guns from that order went back to Smith for modifications. I don't remember what the problem was but they worked fine when they came back and we carried them for several years. The same thing happened after we switched over to the new "L" frame 686. By then we had a S&W trained armorer and he fixed the problem and we carried those for a few years and it's been Glocks ever since.
All makers, even unto this day, seem to cut loose new products a bit too soon at time. Witness some of the trials with the various plastic fantastic's.

The 681 was largely a product for LE. Some of the very early ones put out for that service were a lot like your department's experience with its early 66-0's.
 
S&W revolvers like yours are intricate pieces of machinery. If they left the factory working flawlessly they likely will continue to do so with reasonable cleaning. Too much lubrication, especially of products that gum with time, will cause them to cease working. If someone who really does not understand them has been inside the lockworks it can be cause for nonfunctionality.

I've seen a few that got pushed out of the factory before they were ready. Most can be made to run like a S&W should; a couple should have been scrapped at the factory.

Not necessarily correct. S&W dry fires to check for function, but live fire is only 3 rounds, then the revolver is considered ready to ship. As mentioned, the first batch of Model 66's had issues related to the heat generated by firing more than one cylinder full of ammo. It is possible that there are Model 66 (no dash) revolvers in circulation that were not sent back for modification.

Since this particular Model 66 is malfunctioning during dry firing, there is something amiss with the lock work. The hand or cylinder stop could be the culprits, but if it only happens on certain chambers, it could be the ratchet. Number the chambers and see if it is a random issue or if it is consistent on certain chambers.
 
OK thank you very much. I will look at these suggestions and try and figure it out. I have many S&W revolvers to use for comparison also.
 
Problem Fixed

Thank you for your input.
I was able to determine that the problem was the cylinder stop. I first replaced the spring with no change. I replaced the original cylinder stop with a used one and the lock-up issue went away.
I noticed when I held the gun sideways against a lighted back ground I could see the cylinder stop drop below the frame and watch the cylinder start to rotate and then watch the cylinder stop come up again on many other revolvers that I owned.
On this particular gun the cylinder stop would drop down and quickly come back up. Sometimes the stop would come back up before the cylinder started to rotate causing the cylinder to lock-up.
I was able to view this action with the side plate off and watched the cylinder stop mesh with the trigger. I assumed that the issue was with the trigger or the cylinder stop. Replacing the cylinder stop resolved the issue.

Thank again.
 
Thank you for your input.
I was able to determine that the problem was the cylinder stop. I first replaced the spring with no change. I replaced the original cylinder stop with a used one and the lock-up issue went away.
I noticed when I held the gun sideways against a lighted back ground I could see the cylinder stop drop below the frame and watch the cylinder start to rotate and then watch the cylinder stop come up again on many other revolvers that I owned.
On this particular gun the cylinder stop would drop down and quickly come back up. Sometimes the stop would come back up before the cylinder started to rotate causing the cylinder to lock-up.
I was able to view this action with the side plate off and watched the cylinder stop mesh with the trigger. I assumed that the issue was with the trigger or the cylinder stop. Replacing the cylinder stop resolved the issue.

Thank again.

Interesting, I just bought a used 18-3 that seemed almost like new but had the same problem as you describe. Like you, replacing the cylinder stop fixed the problem. My original cylinder stop looked like it had been "fitted" by a blacksmith.
 
I recently bought a 19-3 with the same issue.

I determined that the problem was caused by a slight bend in the cylinder stop spring which occasionally would prevent the cylinder stop from dropping completely. I was able to flip the spring around which allowed it to function normally.

Will get a replacement spring at some point.
 
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