So there IS a scientific base, the problem is that there are too many input parameters for us to keep in our heads at one time, too many variables. That doesn't make it a black art. I'd still like to pursue the scientific analysis.
What happens to air at different altitudes, pressures, temperatures, humidities, is after all very well understood and well documented. Nothing new to discover there.
For this purpose, the choice of rifle and pellet and scope height etc are irrelevant so long as they remain constant for the one shooter.
What we are trying to analyse is why do shots behave differently in different localities and conditions.