Sorry, that's not correct.
Holding the S&W trigger back and testing cylinder rotational movement is not a valid test.
The only modern revolvers that lock up tightly when the trigger is held back are the older Colt action revolvers like the Python and Detective Special.
In the Colt's, the cylinder is forced and held into tight lock up when the trigger is pulled.

All other modern DA revolvers like the S&W, Ruger, Dan Wesson, Taurus etc, are INTENDED to be slightly loose at ignition.
Holding the trigger back and checking cylinder tightness is not a valid test in these guns since simply cocking the hammer locks the cylinder as tight as it's going to get.

S&W and the other brands are designed to allow the cylinder to be slightly loose so the bullet passing from the chamber to the bore can force the cylinder into alignment.
Even if the cylinder appears to be tightly locked, there's enough backlash built into the action to allow the cylinder to move and align itself with the bore.
There is no factory standard on how loose the cylinder can be. The only test is accuracy and if the gun spits bullet metal.

Bottom line, A S&W cylinder must be slightly loose in order to work correctly.
Even if it seems to be tightly locked it isn't.