On the contrary, I think the chart supports it. It is not how fast the pressure peaks, it is how high the pressure goes. Black powder gives a gentler longer lasting push; smokeless gives a hard sharp kick in butt! Or, if you wish, a man can push a car and start it to roll, but if he runs at it as fast as he can and crashes into it, the car isn’t going to move (and the runner gets hurt in the process). Experience bears out the analogy. It is smokeless powder that blows guns up, not black powder.