In response to post #9:
I have to disagree, although I should apologize, as I am perhaps not as "well versed" as some, as I only have 36 years of revolver armorer's experience.
I'm totally mystified as to where this notion of "zero" endshake, or "no endshake at all" as you call it, ever originated. Endshake, or gauge in the assembly is not only acceptable, it is required.
First, concerning your description of what happens to the cylinder during detonation, the ratchets never touch or "hit off the breechface" as you indicated....contact between the extractor and the breechface is confined to the extractor boss that surrounds the center pin hole in the extractor body. Wear and tear (not impact peening alone) on the components, including the bearing surface at the rear of the yoke barrel, the bearing surface inside the cylinder at the rear of the yoke cavity, the boss on the extractor and on the breechface itself, ocurrs both during detonation, (by direct and rebound impact) and when the cylinder assy rotates on the yoke. This wear is exacerbated by dirt and debris. Zero endshake will not serve to mitigate this inevitable wear, because the gun cannot function with no gauge within (or between) the assembled components.
Zero endshake is impossible in the assembly, because, by definition, it leaves no room for the components to function. The cylinder and other moving parts simply will not freely rotate as they are designed to do, and in this "zero" endshake scenario you describe, the cylinder assembly cannot even be opened and closed. Add in the inevitable dirt, shooting debris, generated heat and your favorite lubricants and, even in a gun that is cleaned regularly, you have a revolver that simply will not work.
Your comment that in the presence of any endshake the revolver will "batter itself to destruction" improperly assigns fault for "destructive" wear to a single origin. The "destruction" or degredation you allude to is common to every mechanical device, and in the case concerning revolvers it's cause should be attributed to a number of factors, not just the presence of endshake. Righty attributed, the causes must also include: normal contact/friction degredation, neglect, abuse, oxidation and improper use. (and some others)
If the original "factory" fitting of the revolver was done completely and properly, it will have adequate gauge in the fit components, including the required "endshake" if you want to call it that. During the subsequent life span of the gun, the only fitting concern regarding these component parts with respect to the proper position of the cylinder in the frame is the front and rear gauges. If the front and rear gauges are correct, and meet specifications, then, barring any other repair concerns, like the integrity and proper position of the yoke for instance, the revolver in question will operate and function as intended. Stretching of the yoke barrel or the addition of shims may become necessary because of an out of spec condition (wear resulting in an open rear gauge condition), but the focus of the repair should be to restore the rear gauge so that it is within the proper specifications, not to push the cylinder back into a zero, or "no endshake at all" endshake condition.
