Mike Venturino has a book about old west sixguns, and has .44/40 loading tips. He may still advertise it in Rifle and Handloader and Shooting times. It is well worth the price.

I have always been leery of the .44/40 because of the stories that it jammed the guns. I don't know how, but cylinder rotation was impaired. That dates back to black powder days.
I don't know how common it is; saw it in Skeeter Skelton's articles. Venturino hasn't had a problem with it.

On the other hand, the round should work okay on people. Lt. Col. Vincent Fosbery, V.C., who later invented a Webley automatic revolver bearing his name, said that the .44 was the best handgun stopper that he saw in use along the Afghan frontier in the 1870's and 1880's. That carries a lot of weight with me, those Pathan tribesmen being notoriously hard to kill.

I've wondered how an explorer in the 1920's would fare with a Hand Ejector S&W in .44/40. The S&W .44's mentioned by Sasha Siemel may have been these, rather than .44 Specials, as the Winchester M-92 .44 rifle was so popular in Brazil. In fact, Siemel owned one, He didn't always rely on his famous spear with jaguars.

Anyone know what velocity the 200 grain bullet gave from revolvers with factory ammo in the 1920's? I assume that rifle pressure ammo was NOT safe for use in revolvers.

Elmer Keith did NOT like the.44/40, as it gave more reloading problems than did .44 Special, and the chamber thickness of the cylinders was more in .44 Special. With his hot loads, that mattered.

T-Star