not sure if you're keeping up with my thread on here, but I'm having similar issues...
first off, really examine your gun, make sure all the parts are good and that you don't have any problems... I once had a taurus that cracked the forcing cone on the first shot.
If that's not the case, I would guess the same thing is happening to you that is happening to me, had a hard time figuring it out, so I started out like a newbie with the advice these folks have given and am already seeing improvements.
Before, I could from time to time bounce coke cans at 100 yards with a 4 5/8 inch blackhawk in .41 mag, however I was having terrible inconsistency, some times I could pull off those "amazing" shots, and other times I couldn't keep 6 inch grouping at 10 yards. I'm just now realizing my issues, there were a couple affecting me and I'm getting more consistent now. I had been firing rifles so much these past few years, that I have gotten some bad handgun habits from them...
as far as flinching, I saw some great advice... load up your revolver with some spent casings and some live ammo, let your wife shoot it without knowing which ones are which (meaning don't let her see you load it), then watch her muzzle closely as she fires the whole cylinder worth of rounds... Have her do the same thing for you. A flinch will then become quite evident.