Was shooting today & after 50 rounds the hammer won't go all the way back & lock up on one chamber . Doesn't matter if single or double action . The other 5 work just fine . It feels like the main spring is " knuckling " though . Could the ratchet be the problem ? Haven't pulled side plate for inspection yet . Any ideas ?

If you are able, I would try a complete disassembly and cleaning/lubing and then re-check with empty casings in the gun. Pay particular attention to the cylinder assy and the yoke when cleaning. (inside and outside) When you clean the interior parts and frame, look for and clean out any crud in the hand slot.

Check for end shake, and make sure both of the extractor alignment pins are in place. If the hammer is indeed "knuckling", the mainspring strain screw may be loose, or an aftermarket spring may have been used.....although this would not be contributing to the carry up issue.
Check the ratchets for damage using a magnifier if you have one.

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Ret. LE, FA Instr, S&W Armorer

If the problem is consistently on one cylinder tube ONLY, the ratchet is the first suspect. Clean well, tighten screws and check again. You should be able to see the damage to the ratchet if it's there. You can eyeball it just by swinging the cylinder out.

Stripped it down to the frame & put everything in my Ultrasonic cleaner . Lube it up & reassembled . Replaced main & rebound springs with new factory springs . Still have the same problem . Looking at ratchet I can't see anything , but can feel roughness dragging a thumbnail across the teeth . Not sure where to stone / file & can't find my magnifiers or pillar files . Kunhausens book not real clear on ratchet / hand fitting . Anyone have any pics that show surfaces to be fitted ?

pics of the cylinder where it's not locking.

Strongly suggest you do not attempt to file or fit the ratchet unless you know exactly what you're doing; there's quite a few easy ways to foul it, and the fix is more complicated and expensive than simply having S&W or a qualified revolversmith dress one tooth (if that is indeed the issue).

Hap,

if the Chamber in question is not carrying up then that would mean the Ratchet is already undersized and was probably filed too much to begin with - as they should all pretty much wear evenly if everything else is in alignment. Therefore it can (maybe) either be "peened" into a slightly larger size, have a tiny amount added by welding and then reshaped, or get the entire Star replaced and refit.

I agree that for most gun owners that have never done this it is not a project to start out Gunsmithing on. I have done this on an old Revolver one time and was successful, but it took me the better part of an afternoon to get it done. THANKFULLY I did have Factory new parts in stock to do this (thanks to Dad) but would not look forward to doing so again as it it tried my patiences a bit. Had to stone & file all 5 on the new part - the old Star had worn out and was beyond repair.

For a Professional Revolver GS this would not be a difficult task and would suggest he take the Revolver to a highly recommended one.

I too feel that this is above my skill level . Guess I'll send it to S&W .

+1 Gunsmith only job.

Since you call the gun a 586-0 it must be a fairly early gun from the 1980s and only about 30 yrs. old. Lets hope S&W has the old style parts in stock. The new ratchets are way different.

Query: Is it really 586-0 or just plain 586?

Let us know what S&W says.

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Bob.
SWCA 1821

It's really an older 586-0 with the " M " stamp .