Another pressure curve to demonstrate Miller's point
“Powder Pressures At Different Parts of the Gunbarrel”, 1895
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA32&dq The choice of 32 grains of Ballistite is confusing, as 25.5 grains is the published load for a 3 Dram equivalent.
According to
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA7 this is the Dram Equivalent for the grains listed for the Nitro Powders:
Ballistite 32 gr. = 3 3/4 Dr Eq.
Walsrode 34 gr. = 3 1/8 Dr Eq.
Cannonite 38 gr. = 3 1/8 Dr Eq.
Schultze 42 gr. = 3 Dr. Eq.
All 4 curves meet at 6" but at 12" the pressure for Dense Ballisite is 1600 psi by Burrard's conversion; Bulk "Schultze" 1900 psi. The difference continues out to 24". Of course no "progressive burning" powder was available in 1895.