Cylinder play

Nephrodoc · Mar 19, 2012

I was cleaning and lubing my 686-6. I wondering how much cylinder play is acceptable on a 686, and how to correctly measure this. I do notice a slight side to side play, no front to back movement, did this at full lock up.

It is much less play than my taurus revolver, but not sure what is acceptable?

Someone told me that this should be checked with empty casings in place?

Your input would be appreicated...

chief38 · Mar 22, 2012

A small amount of play (side to side) is normal and acceptable and there will more than likely be some charge holes lining up that are tighter than others. A huge amount of play should be addressed. When the trigger is squeezed it should be locked up tight just prior to the time it falls, even if there was some play before the trigger was pulled. When the gun is empty pull the trigger and hold it - then check the play again. If it is locked up tight you should be good to go.

Front to back play should be minimal and not really noticeable. A tiny amount is OK, but if it is too much, it should be shimmed tighter.

I just go by feel, and do not use any measuring devises. After a time period of playing with revolvers you'll get to know what is too much, too little and just right. Hope that helps........

Regards,
Chief38

dfariswheel · Mar 22, 2012

Sorry, that's not correct.
Holding the S&W trigger back and testing cylinder rotational movement is not a valid test.
The only modern revolvers that lock up tightly when the trigger is held back are the older Colt action revolvers like the Python and Detective Special.
In the Colt's, the cylinder is forced and held into tight lock up when the trigger is pulled.

All other modern DA revolvers like the S&W, Ruger, Dan Wesson, Taurus etc, are INTENDED to be slightly loose at ignition.
Holding the trigger back and checking cylinder tightness is not a valid test in these guns since simply cocking the hammer locks the cylinder as tight as it's going to get.

S&W and the other brands are designed to allow the cylinder to be slightly loose so the bullet passing from the chamber to the bore can force the cylinder into alignment.
Even if the cylinder appears to be tightly locked, there's enough backlash built into the action to allow the cylinder to move and align itself with the bore.
There is no factory standard on how loose the cylinder can be. The only test is accuracy and if the gun spits bullet metal.

Bottom line, A S&W cylinder must be slightly loose in order to work correctly.
Even if it seems to be tightly locked it isn't.

chief38 · Mar 22, 2012

dfariswheel:

I respectfully beg to differ with your statement.

First check to make sure your revolver is not loaded, cock the hammer and test for side to side play of the cylinder. More than likely there will be a small amount. Pull the trigger back, hold it and check the play once again. The cylinder will lock up tighter than it was prior to the hammer falling due to the fact that the hand has moved up holding the cylinder in a tighter position. You can actually see his happen (watch the hand) if you do this with the cylinder swung out and pull back on the thumb piece release which will allow you to cock the revolver with the cylinder opened.

This is the case with each and every S&W I have ever seen. Now I am not saying that if you exert enough pressure the cylinder will not move at all, all I am stating is that the pulling of the trigger which raises the hand to its most upward position will tighten up the cylinder more than it is prior to pulling the trigger. Some slight amount of play is essential, but the cylinder will be noticeably tighter than prior to pulling the trigger all the way rearward as it is when fired.

I have never known a S&W revolver not to act this way.

As I am sure you already know, the job of the forcing cone is to help the bullet align with the barrel in case it is not 100% lined up already. Revolvers that are badly out of time will exhibit heavy leading, but the gun should still fire without any incident.

Respectfully,
Chief38

dfariswheel · Mar 23, 2012

That's not way the hand on a S&W works.
In the old Colt's the TOP of the hand presses against the ejector ratchet lug. The harder the trigger is pulled (within reason) the tighter the cylinder is forced into lock up by the hand pressing the lug.

The S&W hand operates by the SIDE of the hand pressing against the ejector lug. Once the cylinder is locked, the hand bypasses the lug. Once the hammer is cocked and the cylinder is locked, no amount of pressure on the trigger can force the cylinder into a tighter lock up, because the hand simply slides past the lug.

While the cylinder may seem tighter with the trigger pulled due to spring pressure, the built in back lash allows the cylinder to move enough to allow the chamber to align with the bore.
I suggest reading the Kuhnhausen shop manual on how the S&W action operates.
He clearly addresses the S&W design of both how the cylinder is designed to remain slightly loose, and on how the S&W hand operates by bypassing the ejector lug.

Once the hammer on a S&W is cocked, it's as tight as it's going to get.
The only way the S&W action could lock the cylinder tighter is if you used a tapered hand that could press harder against the lug. S&W hands are not tapered in thickness.

chief38 · Mar 23, 2012

Well I guess we'll just have to agree to disagree, because every Smith I own and have ever worked on DOES get tighter when the trigger is pulled and held. The hand DOES continue to move upward ever so slightly from the cocked position to the release position. It's just the way it is.

Regards,
Chief38

dfariswheel · Mar 24, 2012

Agree we disagree.

Of course the S&W hand continues to move upward as the trigger is pulled, but unless the hand gets thicker (which is doesn't) the hand is simply bypassing the ratchet lug.
Since it's simply sliding past the lug, the cylinder isn't being pressed any tighter into lock up.

Cylinder play

Nephrodoc

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