DJ,
It is known that the early 44 W.C.F. / .44-40 smokeless powder used by the factories was DuPont #2 Bulk Smokeless and 17 grs was the charge which filled the capacity of the case. H4227 produces pretty much the same velocity (1,300 f.p.s.) at the same 17 gr charge weight, so the burning rate between the two powders would be similar.
Unfortunately, I have never seen any data on the pressure and duration of the DuPont powder but back in 2004, I had an aquaintance that worked in the Hodgdon's ballistis lab and he pressure tested some 44-40 ammo that I had given him. The loading was 200 gr cast bullet / 17 / 4227.
Pressure wise, it generated around 14,000 PSI. The early b.p. load was said to generate around 15,000 PSI. I did not receive any pressure traces but I would expect it to be similar to the graph below which compares 4759, a powder with a burning rate pretty much identical to H4227 (and to DuPont #2), to BP and Trailboss. Note the high pressure of Trailboss (33,000+ cup !).
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