That part of the recoil movement that takes place between ignition and the bullet exiting the muzzle is termed "jump".

The most straightforward illustration of this in fire arm design is the fact that the front sight on a heavy caliber revolver is noticably higher than the rear sight so the axis of the barrel is pointed downward when the sights are on target.

It's been my experience that those who claim there is no such thing as jump will not be convinced no matter how much evidence for it you come up with.