I was shooting my 625 JM in a USPSA match yesterday and had some problems with the strain screw backing out one full turn and causing mis-fires and then the yoke set screw for the cylinder yoke also backed out enough that on a reload the cylinder went too far forward and I could not close it. Back to the safety area....Darn it anyway......

Lesson learned is to check ALL screws for proper tension BEFORE the match not in the safety area!!

Which Loc-Tite would be best to use to ensure that this doesn't happen again? Loc-Tite Blue?

Randy

I wouldn't use the red loctite, unless you never want to remove those screws again.

Knew about that one.....but thanks for the reminder!

Randy

fingernail polish works too

Neither screw should back out if torqued properly. There is no strain* on the strain screw. The cylinder retention screw (there's a better name for it) also serves as a pivot for the crane. Any Loc-Tite on the threads is likely to bleed into the crane shaft. This screw may have a spring loaded detent in the tip, which may be damaged or missing.

Strain screws have been loose on several used and new S&W revolvers. Once tightened properly, they haven't shot loose again. I suspect tampering by amateur gunsmiths to lighten the DA trigger.

One possibility for the latter crane screw is Loc-Tite "Purple", which is low strength, high viscosity for sealing bearings with loose running fits. I would apply it to the threads of the screw only, and only as a last resort.

A torque screwdriver handle is a good thing to have in your tool kit. They accept hex shaft tips, which must selected to fit the screw head perfectly.

* strain is stress (force) plus motion or distortion.

put a little gun oil on them and tighten up.

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Mike
S&WCA #3065

I used the blue on my 986. Works for me, does not come loose and can take it out if needed.

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Nam '66-67

One thing that works,does not use loc-tite and is in the possession of most men is Spiderwire or any other mono filament.
I own a Ruger that is always trying to self destruct and I place a short piece of Spiderwire in the screw holes,replace the screws and tighten.Any extra filament can be cut off and you are good to go.

See my thread here. Alot of discussion on loctite.
Screws Loosening during shooting-Use Loctite?

Randy, start with clear nail polish on the threads and properly set all screws. Good luck.

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Always Stay Strong!

I've only used blue LocTite on scope rings, scope bases and gun screws, etc. I never needed anything else, as long as I clean the oil off the screws with alcohol.

Purple loctite first. If they loosen up then go to blue loctite. Never, ever red.