I have a new to me 58 that appeared unfired when I bought it. The problem is from the start it will fail to rotate cylinder on average once per cylinder full. The gun is very clean and was cleaned again after problem arose. It fails on random chambers, not the same one every time. It does this in single action or double. The hand and hand spring seem fine, had a gunsmith check it out and after getting it back a month later same issue, he said he cleaned up ratchets on extractor, but no change. Any ideas on what might be problem? Any help or ideas appreciated.

Pull the sideplate and look in the back of the hand window while you carefully cycle the action so you can see how the hand and ratchets interact. You may want to take out the mainspring and hammer to take stress off of the hammer pivot pin and make the action easier to work.

My regret is it is currently back at the gunsmith, I'm giving him the opportunity to figure it out, but confidence is not high. I wish now I'd kept in hand to try and figure it out, but I want to know what to look for when it comes back in same condition, hopefully he figures it out, if not I'll take any and all advice I can get. Thx

The hand rotates the cylinder. The hand spring sounds suspect. If your gunsmith had it a month and didn’t fix it, get it back now. The factory will fix it or find a factory armorer near you.

Could also be a problem with the hand's proper intrusion into the hand window. If it's not correctly fitted, the hand will not reach and interface with the ratchets properly.
Another thing to check would be the rear gauge, or headspace. If this is out of spec, (end shake) the cylinder can actually be forward enough that the hand cannot pick up the next ratchet properly.

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Ret. LE, FA Instr, S&W Armorer

Definitely get it back from the "gunsmith" that has it now. If you don't have anyone local who can actually repair it, send it to one of the many highly skilled gunsmiths available in the country.

I'll get it back this coming week fixed or not as gunsmith has no authorization to do any work other than diagnose without my OK.

ken158; he had it a month only because he's pretty busy, doubt he spent a month not figuring it out. He thought it was a simple matter of touching up the ratchet, but that turned out to not be the case.

armorer951; if any thing like headspace or endshake is out of spec it came that way from factory as this gun appeared unfired when I got it.

Giving benefit of doubt to gunsmith as he thought he had it as he couldn't replicate problem in his shop. I gave it to him without grips or ammo, he gave me the option of giving it a try myself or waiting for him to do it after putting on grips and getting some 41 ammo

I doubt the problem with the ratchet. Very likely the hand, its spring or the little window thee hand works through. The ratchet will effect timing but not failure to rotate

I would say you have one Ratchet that is a wee bit to small and possibly in conjunction with a Hand that is also a little too thin. I would start with a new Hand - might have to use an oversized one and fit it to the SMALLEST ratchet. You first MUST isolate the problem Charge Hole to properly fit.

You should also check for Cylinder wobble or out of round turning. Is your Cylinder locking up properly and consistently?

The hand should be 90 degrees to the trigger in order to fit through the frame window. if not it can bind. The pin through the hand can be bent slightly to straighten the pin so that the orientation is correct. Leave it in place and put pressure on the point of the hand. Take a look.

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Made it, Ma! Top of the world!

The torsion hand spring may have a small sharp burr on the end of the arm where they are clipped off during mfg'r. The one end engages the hand pin .

That sharp (and very hard!) burr can be running against the inside of the cut of the trigger and can occasionally snag the spring in the compressed position when the trigger is pulled.
That leaves the hand with no spring action on the next trigger pull, it's just flopping back and forth and a fail to rotate the cylinder is a very good possibility (unless the gun is pointed downwards and hand falls against the ratchet).

That false pull will usually pick up the snagged spring once again and engage it and the gun seems to function fine there after.,,Untill that nasty little burr just barely catches itself into the wall of the cut inside of the trigger and hangs up again.

The trigger is casehardened, but the hard spring wire will wear through that in no time especially a sharp chisel like burr on the end from a snip-cut off operation done during it's manufacture.

Just something to check for,,may not be the problem at all.
But it takes nothing to check other than very close examination and costs nothing remedy other than a stone or diamond lap to the end of the spring arm.
Make sure the spring arm isn't bent also..

This most closely describes what seems to be happening and would explain intermittent and random nature of the problem. Hope this proves to be the case.

Have you talked to S&W?
Steve

Got it back today and took it to the range. Same problem, but with less frequency. Shot 88 rounds of mid-range handloads and had 5 failures to rotate, never happened twice in same cylinder full and several failure free cylinders. Might be working itself out with continued shooting? Will take it apart soon to look for the sharp dragging spring as 2152hq mentioned, as that sounds most like what seems to be happening. Will report back when I find out more.

My money is on hand spring given virtually new, but aged condition

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Some collect art; I shoot it!

Shot it again yesterday, and only one failure out of fifty rounds fired. I did take it apart as far as I was comfortable with and saw no obvious problems or wear spots. I did not take the hand spring out of trigger, but did remove hand , and that end of spring and hand pin looked OK. Will shoot it a little more as problem seems to be getting better with use.

Maybe do a complete cleaning of internals or have someone who is familiar with this, you never mentioned
if this pistol is an older one or one of the newer ones? If an older one maybe old grease or maybe WD40 is
gumming up the works?
Steve

Cleaning was first thing I did to this older but virtually unfired gun. Haven't revisited this issue for a while, waiting for it's turn in the safe/range rotation.