Cylinder contacts forcing cone when closing

[jw8265]

just noticed today when cleaning my S&W 10-5 that when the cylinder slightly contacts the forcing cone on the lower left side of the forcing cone. Once the cylinder is locked in place there is no contact. What is causing this and how can it be fixed?

It does not happen at all after the cylinder is fully closed or when trigger is pulled, just when closing/opening the cylinder. It seems that when the ball detent (not sure of the actual name for it) on the extractor star is being depressed it pushes the cylinder face against the forcing cone slightly. Once everything is locked into place it functions normally when pulling the trigger and at lock up.

 

[jw8265]

I read on another thread about these cylinder bearings http://www.brownells.com/.aspx/pid=9858/Product/CYLINDER_BEARINGS

Is this an option or does a gunsmith need to work on my issue?

 

[Culina]

Yes, put one or two bearing in there, that should fix the endshake problem nicely

 

[jw8265]

Do I need cylinder or yoke or both bearings?

 

[HEADKNOCKER]

That matters if the "Play" is in the yolk or the cylinder..
You can measure it with feeler gauges with the cylinder pushed forward & pulled to the rear & then subtract to get the amount of endshake your trying to shim out..
Also some slight bit of endshake is needed to keep the cylinder from binding, expecialy when dirty..
I'll also mention that the .002" shims I've bought were "ALL" .0015 thick, as I measured each one with my handy dandy Digi Calipers..
Makes a big difference if your trying to shim .003" & think that two shims is too thick..

 

[blackpowder30]

There is a video on YouTube Gunsmith that tells how to install the shim bearings, if you are so inclined.

 

[jw8265]

I tried to measure the end shake and it is not consistent throughout the each rotation. Is this normal? For most of the measurements I wasn't able to get the smallest feeler gauge (.0015) in between the cylinder face and forcing cone while pushing the cylinder forward (but I can see a gap when holding it to a light), and got .007 for 5 of the measurements when pushing the cylinder backwards. For one of the measurements I got .0015 and .006, meaning that the end shake for this measurement is .0045 correct?

What is considered normal for a S&W revolver for end shake, cylinder gap & head space?

 

[David Sinko]

My very expensive Bowen Redhawk Alpine Conversion does the same thing. Mr. Bowen has subsequently examined this revolver and told me that it is perfectly normal and there is nothing wrong with it. I realize that a Redhawk is not exactly a Model 10 but there is still a chance that nothing is wrong with your revolver either.

Dave Sinko

 

[500 Magnum Nut]

As the gun wears it will loosen up. Sometimes this condition is caused by abuse as the yoke is twisted out of alignment. In the FAQ sticky above I have the tolerances listed for using a feeler gauge. It also covers how to adjust the yoke if peening the button is required.

A larger cylinder air gap will correct this problem, but normally a gap of .003-.004 is preferred for several reasons.

If the end shake needs adjusting this will correct the cylinder touching the forcing cone. This is corrected by stretching the yoke barrel or adding shims (bearings).

If the yoke is loose fitting, determine what is worn. You might have to tighten the button to suck it tighter into the frame. If the yoke stud is loose fitting, order another yoke screw and fit it so there is drag on the yoke as you close it. This is done by filing the end of the screw. Another option is to swap the bottom screws of the side plate, again fit the screw if it's too long.

Third thing is the yoke itself could be misaligned. This is checked with a yoke centering gauge. If the yoke is found to be out, it can be pressed back into alignment using a wedge and or a hammer depending which way it's misaligned.

Sometimes, the yoke barrel or stud is worn so a new yoke will correct the excessive wobble. Might not be an option on an older gun where parts are not available.

Shooting it at the range won't hurt or affect the gun if the problem is only slightly rubbing the barrel (for example .001-.002 off).
If replacing the yoke is the only cure, perhaps living with it is the best approach.
No gun is the same and your dealing with tolerances stacking up to affect the condition. Even after tightening up a gun, the problem could still be there.