Hi"
I have a Model 65-1 that with the cylinder (with thumb pressure) pushed to the rear measures .008. Pushed forward the cylinder is against the forcing cone.
Opinions ??
Thank you,
Jimmy

The condition you're describing is called "endshake" and .008 endshake is far too much. Your gun is beating itself to death every time you fire it. Endshake can be corrected by any competent gunsmith for short money (my smith charged $25 the last time I had one done), and you should get it fixed before you use the gun again.

jimmyj,
There is a very good video put out by Midwayusa on fixing the end shake B/C gap. It looks pretty darn simple to do with only a screw driver, feeler gauges and shims available from Midway or probably several other places.
If any of my S&Ws ever need it I will try to do it myself.
And I can't make a soup sandwich with out messing it up.