I have been loading for a Miroku/Winchester 1892 44/40 for three years. First of all not all brass is equal. Winchester brass is extremely thin in the neck. It is supposed to be that way so that the brass will seal the chamber at the low SAAMI spec pressures. You have to be very careful when seating and crimping or the necks will collapse. Get the bullet straight before running it into the seating die. Get adequate flaring of the case mouth is critical to bullet seating. I seat and crimp in separate processes. I have RCBS dies but use a Redding Profile crimp die to do the roll crimp. IMO this is the only way to go. Technically 44/40 barrels should use .427-.428 bullets but the new Winchesters are usually .429 and the bullets should be .429 or .430 to shoot best. This is the biggest reason to exercise extreme care in the seating and crimping. You need good dies. I have little faith in the Lee stuff especially the factory crimp thing. Resist the urge to shoot heavy 44 bullets. Restrict yourself to cast bullets in the 200-220 weights. Don't try to magnumize this round. The 44/40 is not a magnum but an effective round on its own. Higher pressures cause early case failure. I use Winchester and Starline cases mostly but I have some Magtech that I got as factory ammo that I use and got to work well using the Redding profile crimp die.
The 44/40 is pure fun to shoot. Low recoil even when loaded to 12-1300 fps range. Rounds feed best if you stick to bullets that are or closely shaped like RNFP types. I have had great results using the Nosler 200 grain .429 bullet at standard velocities.
If you get in a hurry or try to take shortcuts you will ruin a lot of brass that is expensive and difficult at times to find.