Originally Posted By: builder
The chart seems to show there is no difference after 2" which is within the chamber.


That is indeed what Drew's graph shows: No discernible crossing point. The often-cited Dupont graph (from 1933) shows a crossing point at about 2 1/2", where the lower pressure loads overtake the higher pressure loads. That same graph shows that by the time they reach a distance of 7", there's a spread of about 500 psi between high and low. And by the time they reach 10", there's no significant difference.