Nice pictures, but a pistol isn't going to react much like a 8# shotgun braced against a shoulder. The pic illustrates lateral movement and it is true, from what I have read, that a SG also moves laterally toward the shooter due to recoil. By the time the shot cup is out of the muzzle, about 0.3 inches, which takes about 0.003 seconds from time of ignition. During that period, I question just how much barrel rise occurs and how much it affects point of impact.
Going back to that pistol photography, and the other pics, especially the post immediately prior to 168, it does look as though muzzle jump occurs after the pistol bullet is out of the barrel.