CYLINDER ENDSHAKE

[sensei]

Hi all,

For all of you that have practice in Gunsmitting, (in particolar S&W 625 )

In yours experience how the "cylinder endshake" can be the reason of a bad igniction (with the Fed primer too ....), i try to explain better, .... the little "shake" of the cylinder, in a Revo with a light trigger pull, during the fire, can be another cause of some missfire ?

And the "cure" could be the Power Custom bearings ?

Which are your experience about ?

Thank you Boys.

P.S.

I am VERY near to take the Master card in Revo Division, ..... I HAVE to stay in about 83 % in 2 matches ...... ..... no bad for the first year in the wheelgun Division .... ....

(Alain Della Savia, ... please GO SLOW !!!!) ...

[RPM8shot]

sensei,

If the enshake is excessive more than .006", then you may experience some ignition reliability problems. any endshake in excess of .006" should be corrected by stretching the crane and refacing the crane.

Endshake not in excess of .006" can be corrected using the Power custom shim.

I call this "the repair before stretching the crane".

Some endshake is not bad. I prefer to have the gun set up with .001-.002 endshake. ICORE/IPSC revolvers tend to run a little dirty so the endshake is just a safegard.

In my 625-3 I had .005" end shake before I tightened it up with a .004 shim.

In addition, ensure that there is not endplay in the yoke in the closed position. Yoke feels like endshake. You need to pay attention where the movement is coming from. Yoke shake is checked with the crane in the closed position with the crane moved fore and aft along the barrel.

(NOTE: If you have one of those spring loaded yoke screws, then you should not have any yoke shake)

FOr Light strikes:

You may want to check your hammer tension if you are getting light strikes with Federal primers. I have found 32-36 oz enough to reliably ignite Federal primers. I use a Miculek spring kit tuned to 6 3/4 lbs.

You can check hammer tension with the trigger held down and the hook of the trigger gauge under the hammer nose or hooked on the hammer.

You can also clearance the face of the hammer to allow the firing pin to sit deeper through the recoil plate (firing pin bushing hole). Be sure to clearance the end for the hammer nose so it does not bottom out in the hammer. If not you could snap off the top of the hammer nose. You can relieve the hammer up to .015". This will get you about .015 more hammer pin protrusion.

If you have a frame mounted firing pin, the C&S extended pin (+.015") is a good swap. Remember to polish the pin be installation.

Also you can tune your ammunition by ensuring that the primer is pressed .004" deep.

This is just my experience for what it is worth.

Hope this helps,

RPM8shot