Back when I was a member of NRA's BBS board (Anyone here ever go there back then? Used to be in the early 90s.) we had a big discussion about recoil. When does it actually begin, what factors control the amount of felt recoil, and when does recoil end.
The photo seems to lend credence that recoil begins upon impact of the firing pin on the primer. SOMETHING pushed that hammer back like that. So it implies that a fired cartridge gets struck twice by the hammer in a revolver.
So did that picture catch the action at precisely after the cartridge ignition threw back the hammer, but before the cartridge case impacted the frame to impart a recoil pulse to the gun??
Also, since we see no muzzle rise, the projectile has also exited the barrel before muzzle rise even begins to take place? I always thought the general rule of thumb was that heavier bullets shoot higher on the target because muzzle rise is greater than with lighter bullets. But maybe it's not the weight of the bullets at all, but instead the speed of the bullet and how long it takes to exit the barrel before recoil even starts.
Like I said, neat shot! And very thought provoking as well....