One point I'll make about weak hand reloads and S&W revolvers: The yoke screw is a S&W's Achilles heel. It's the only thing keeping the cylinder from falling off the front of the gun when opened. During a weak hand reload, the cylinder's unsupported, so force from behind can bend that screw and wreak havoc. Newer guns have a spring-loaded plunger at the base of the screw, and unsupported force can eventually override the plunger entirely, in which case the cylinder falls out of the gun, and the damaged yoke has to be fixed by S&W.
That's why I try to put very little force on the cylinder in that direction, but I suppose that under stress I might unintentionally slam the cartridges in there.
Admittedly, I haven't given it much thought because I personally use autoloaders for defensive purposes and do not participate in competitions (for now, anyway).
If I were to use a revolver in anything other than a backup-to-a-backup role, then for a S&W revolver I'd likely fit a high-grade screw to the yoke (or some other strengthening modification), have the cylinder cut for moon clips, and the charge holes chamfered (minimally). If I change my mind about the moon clip mod, then I would probably switch from my old twisty speedloaders to something like the Safariland COMP II, and support the cylinder while pressing the release button (sort of a pinch). Of course, at that time I'd seriously experiment with other reloading techniques, as well. Obviously I'm no authority on this subject, to put it kindly, but I did want to bring up "weak" hand revolver reloads while we're at it.
It's a bigger issue with push-release-type speedloaders.
What if I used a low-profile push-to-release speedloader and pinch technique to release? I haven't tried this myself yet, but it would seem to be feasible.
Ouch. Yeah, I should mention that even though they're just dropped in, rather than actively pushed, moonclipped guns are susceptible as well. I've seen a few cylinders with moons launch.
With that little force, I'd think that this would at least partially be the result of cumulative wear & tear on the yoke screw. If not, then that's pretty alarming.
I've had good luck thus far, although I've heard of others having problems, which I chalked up to defects, wear, or harsher abuse than dropping in moon clips. I've always been more afraid of accidentally bending the ejector rod while under stress.