My S&W Model 460 surprised me the last time I shot it:

Five shots, .910" at 100 yards off a benchrest. The load was 200 grain Barnes XPBs over 46.0 grains of Accurate No.9. I would have been perfectly content with a group twice that size at that range.

This probably isn't the best standard to hold a revolver to, though. My 460 is more akin to a specialty pistol than a revolver in terms of size and shooting requirements.