All of the infographics on that site don't show bullets being fired, they show whole cartridges. It's also talking about bullet weights and speeds, and completely skips the concept of "energy" (i.e. Joules) which is what actually matters for this analysis. Additionally, they seem to assume that the trajectories are always perfectly ballistic, and that the projectile never begins to tumble or otherwise present any sort of wind resistance. It just screams that the people involved in the process have never actually been anywhere near any firearms.

This makes it extremely difficult for me to believe that any sort of intellectual rigor went into any of it. Not that I believe firing guns in the air is a good idea, mind you, but this is lazy.