With the help of a few folks I wrote up this article. I think it's 99% accurate. Help is always welcome at correcting inaccuracies mostly do to the lack of historical information..
"Dupont #2"
"Twenty two years after its introduction, the first .44 W.C.F. smokeless powder cartridge is found in Winchester's catalog No. 55, dated August, 1895. In its manufacture, Winchester used 17 grains of DuPont No. 2 which was a "bulk" type smokeless powder patented on August 22, 1893. DuPont's description of "bulk" smokeless powder indicated that it was to be loaded in "bulk" measure just like black powder.
In the .44 W.C.F., 17 grs. of DuPont No. 2 Bulk Smokeless occupied the same volume as 40 grs. of FFG. Velocity was cataloged at 1,300 f.p.s. for a 55 f.p.s. increase over the the black powder cartridge. To identify the new .44 W.C.F. smokeless powder cartridges from those containing black powder, which looked identical, Winchester put a "W" in a circle on the primer." Dupont #2 had a similar burn rate as today's IMR-4227. However, Unlike 17gr of Dupont #2, 17gr of IMR-4227 is not a case capacity load but is a published load. Also unlike Dupont #2, IMR-4227 is formulated in a way that retards burning which prevents high pressure spikes.
Lyman's 49th lists a max load, 17gr of IMR-4227 with a Lyman 427098. They claim 1,083fps with no pressure listed for Group I rifles like the Winchester 73'. I tested 17gr in my 20" MGM barrel I used for high pressure testing. 17gr with a 427098 resulted in 1,127fps (closely replicating modern Winchester Super-X ammo velocity) @ 9,500psi. I tested 20gr with a 43-215C (427098 replica) resulted in 1,418fps @ 16,500psi but also included .5cc of PSB shot buffer to keep the powder at the back of the case. IMR-4227 is position sensitive and could be why some of my early velocity tests were lower than the manual.
Lyman's 49th handloading manual shows a max load of 18.5gr of IMR-4227 with a Speer JHP@ 1,212fps. This load only gave me 1,097fps. 20gr of IMR-4227 produced 1,297fps but also created 12,000psi, just a tad over the 11,000psi max. A caseload (26gr) of IMR-4227 with the popular Magma type 200gr lead bullet resulted in 1,733fps but produced 20,913psi....only safe for Group II rifles like the Winchester 92/94 and Marlin's 1894. I am getting consistent 10 shot 4" groups at 100 yards.
22gr with a Winchester 200gr JSP (.425) produced 1,386fps at a lower 12,000psi, which closely replicated early Dupont #2 velocities. I also tested black powder loads in semi-balloon head cases and got a consistent 12,000psi, so I feel safe using 12,000psi loads in my Winchester 73 replica and revolvers with .425-.427 lead or jacketed bullets.
Because of my black powder results using semi-balloonhead cases, I am beginning to think that original BP and smokeless factory loads produced a consistent 12,000psi to 13,000psi. I have yet to see original factory data other than 22,000cup for the High Velocity loads that produced 1,500fps. It would appear that Dupont #2 powder was not coated with a flame-deterrent coating that would retard burning thus causing high pressure spikes and may be why Winchester advertised their new smokeless powder ammunition to NOT be used in revolvers...referring to those black powder frame revolvers.
44-40 Website - https://sites.google.com/view/44winchester/chasing-the-44-40