How to reliably measure the time it takes to recenter after firing in Call of Duty?

I have been searching through many different forums to try to find this but I cannot find it anywhere. In Call of Duty, how can you calculate the time (in seconds or frames) it takes for a gun to return back to the center of the screen after firing?

Since the position caused by recoil will be different every time it may even be better to just calculate the speed (degrees per second) at which the gun moves back towards the center. I realize that the stat "Centerspeed" is relevant here but I'm not sure how it's relevant to the calculation.