Target like bull's eye or like combat or like steels?
I can routinely ring a steel torso at 100y with my Ruger Security Six and my handloads. I'd guess I could do it with factory ammo, too, but factory ammo is for chumps. I'm 100% on torso with my GP100 Match Champion at 50y. I wouldn't say either is the MOST accurate, as I've not tried a whole bunch of revolvers in that price range Dan Wesson revolves usually get high marks in the accuracy department, but I've not owned one.
I would suggest that most any modern revolver in the $500-$800 range will outshoot the shooter. The major things to look for are a grip (or stocks) that fit your hand and sights that are appropriate for the type of shooting you want to do.
I like the looks of the GP100... Do you think that shoots better than a 686?
I don't have the answer to your question but I can say this, I had an old man deputy sheriff snatch my .357 Ruger sp101 snubby from me and put 5 bullets through a hole you could cover with a quarter dollar at 50 feet. Rapid fire to boot. He had been watching me make a circle about the size of a dinner plate and he couldn't take it any more. He then continued prowling up and down the firing line hollering "It ain't the gun gentlemen, Practice, Practice, Practice!
The guy next to me and I were so incredulous at this guy's shooting skills that we busted out loud laughing at his ridiculous accuracy. He then hollered out "The shooting range is a serious place gentlemen, There will be no frivolity on the firing line!"
So..... I don't know what make or model is the most accurate, I just bet that the worst of them are more accurate than your hands are!
The most accurate one is probably whatever Jerry Miculek is shooting.
I have a Rossi with a 6" barrel that is awesome. I love that gun.