A great deal of us have seen the pressure curve chart, but maybe not as many have seen the whole description.
Note: It is my understanding from the information below that the powder charges were changed for each shot in order to maintain the same velocity...something not done during my testing [rifle loads] a while back. In my tests, the pressure curve results were based on a specific powder charge, not a specific velocity. Although my charts do not show for same velocity, this is evident enough that one should not load the 44-40 based on "velocity" as many have said. Aside from strong action rifles, with certain fast burning smokeless loads, one would never be able to achieve 1,300fps in a rifle without surpassing max pressure published loads and no signs of such high pressures on the primers.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40