I have a S&W M 64-6 that does not have the usual two clicks when pulling the trigger. It is a DAO gun. The cylinder stop drops fine and releases the cylinder properly, it also returns up well with a barely audible click, the second click as the stop rests in the cylinder stop notch is normal and proper.

I had never had this before and have taken the the stop out and checked it and the spring, both look fine and the stop does not bind in the window.

My guess is that the spring might be a little bit weak, though when pressing on the bolt stop, it seems to be about the same resistance as my other K-frames.

Did anybody experience this before and did a spring change help?

When do you hear the single "click", when the cylinder stop disengages the trigger, or when it drops into the the stop notch? If the latter it is likely that the cylinder stop is barely clearing the surface of the cylinder and has nowhere to drop to, hence no first click. If this is the case you are very close to needing to have the cylinder stop replaced. Shortly you will begin to feel a distinct "catch" when the cylinder starts to rotate because the stop is barely being pulled down far enough to allow the cylinder to rotate. A stronger cylinder atop spring will aggravate the situation.

If you don't hear the second click, when the stop drops into the stop notch, try simply cleaning the stop notches with a toothpick. It may be no more than debris in the notch cushioning the fall and muffling the sound.

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Gunsmithing since 1961

+1 to alk8944, plus look in the frame around the "window" for dried grease and debris holding the stop down a bit from full engagement.

Alk8944 and Keith 44,

Thanks for your replies. I had taken the gun apart and cleaned it thoroughly but it did not improve things.

The first click is missing, the second click for the lock up is good. The bolt stop is unlocking and locking at the proper time and only the absense of the first click puzzles me.

Alk8944,

you were absolutely right with the cylinder stop not dropping far enough. I checked how far it dropped and compared it to the "normal" guns and found a noticeable difference. So I changed it against a non-MIM that I had in my parts box and it made all the difference!

Thanks