cmac: one thing to look for is a cylinder that does not lock up when the hammer is cocked back full, or if you get rotation when the hammer is either locked back or in full battery. If that happens, she's loose. Some of the older Colts or S&Ws (1917s, both) had an older style lockup that held the cylinder firmly in place only after the hammer was released by the trigger.
Another thing to look for is the matchup of the crane to the frame. The crane is that part of the revolver that the cylinder mounts on. If, when the cylinder is fully closed you see a noticeable gap at any point along the crane to frame fit, she's loose.
The advancing pawl - that little arm that rotates the cylinder when the hammer/trigger are pulled back may be worn, or the ratchet on the back of the cylinder may be worn. Look for wear or broken edges on the end of the pawl (advancing hand, par'n me) and look for galling and burrs on the ratchet on the back of the cylinder. Those will indicate looseness.
Another item that does not relate to looseness but the overall quality of what you're looking at is the cylinder to barrel gap. As you rotate the cylinder it should be consistent. That is, you should not see the cylinder get closer or farther away from the back end of the barrel as you turn the cylinder. If you see that, she may be out of alignment. Also, if the barrel to cylinder gap is too large you may suffer lead spitting and a lot of cylinder flash, as wellas burnt or unburnt powder particles coming back at ya.
Of course, if the action is difficult to work or too stiff, you should have a question as to why.
Sometimes, factories like S&W will customer service an older revolver into a sweet new piece for you, relatively inexpensively, if you are just dead set on that one revolver and can't find a better example. So, even if you do locate a clunker that you can't live without, it can probably be made right for you. HTH. Mikey.
