IMHO, your 'end shake' clearance is too tight. And, the symptoms you describe indicate to me that the end of the yoke tube is probably not square with the axis. We all ascribe to the principle that the 'end shake' should be as little as possible, but Zero End Shake is not the way the S&W design works best. .... Every revolver needs clearance for the yoke/cylinder assembly to open and close while hot and for the cylinder charged with cartridges to rotate using the only lever power of the trigger/hand assembly. If your extractor plunger tube is tight and cylinder pin is not too long, it leaves only that the end of the yoke is pushing the cylinder to the rear too much. The fact that you can rotate the cylinder and 'find' a spot that the cylinder will close more readily indicated that probably the end of the yoke is not square with its axis. This is always complicated by manufacturing tolerances in each and every piece of the assembly. IMHO, you ought to measure your end shake with feeler gauges and file 'squarely' a couple of thousands off the end of the yoke tube. Go easy here and use a very fine file and make sure you are capable of filing the end of that tube squarely. Dykem is your friend. Check the breech/cylinder gap before this is done to see if it is going to let that gap get too close.
Every revolver needs a little operational clearance here and there to let every function work easily and properly. Two or three thousands of end shake is a good thing especially in a hot cartridge revolver being shot multiple times. Metal expands as it is heated. ............