Just got back from shooting my recently bought 25-15, as I was about to close the cylinder on the last of my loads and found the cylinder wouldn’t latch shut so I’m thinkin what the hell? Anyway after trying a few more times I happened to notice the cylinder latch and spring laying on the bench then I noticed the detent pin that holds the assembly was loose and slides in and out very easily. I put it all back together and it’s fine now but here’s my question, anyone else have this problem? I debated as to if I should use a drop of blue loctite to assure it won’t comeviytvagain, yes or no?

I'm not sure what you are referring to in your post (there is no "cylinder latch" in the S&W model 25), but I think your referring to the front locking bolt assembly. If this is the case, you could use a very small amount of thread locker on one end of the pin. The problem with this locking liquid is it can wick into the mechanism prior to setting, and cause big problems.

The other possible solution would be to use a small 4 oz. hammer to slightly peen one end of the retaining pin. During re-assembly, the non-peened end of the pin is inserted first. The slightly oversized peened end of the pin keeps it from coming loose, after it has been fully re-assembled.

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Ret. LE, FA Instr, S&W Armorer

A very slight bend in the pin will also work.

Ahh locking bolt, forgive my terminology. I like the second option best I think rather than loctite. Thank you both.

+1 for a slight bend.