The .44-40 was originally a BP cartridge, but with Winchester's intro of the '92 cartridge pressures could be much higher. Cartridges with muzzle velocities up to 2000 fps second were soon being sold, and labeled as "rifle". Of course enough people chose to ignore that label and blew up handguns with them. So it wasn't too long before all .44-40 were made "safe for all firearms". Your Remington was most likely a smokeless cartridge, since it hasn't decayed nearly as much as the .45-75 cases. The BP fouling, if not cleaned out of brass, will erode it in a hurry.
I''m not sure if the .45-75 was ever made in smokeless powder, but I'd guess it wasn't.
I''m not sure if the .45-75 was ever made in smokeless powder, but I'd guess it wasn't.
