Texvol,
I agree with everything James Gates said. After all I'm a .45 Colt junkie!
However, if your goal is for your rifle to be historically correct, the originals were only made with a .44 caliber bore. It fired the .44 Henry rimfire cartridge, however, not the .44 W.C.F., otherwise known as the .44-40.
Fortunately, I have an 1873 Winchester in .44 W.C.F. which was made in 1882. As James said, the brass is thinner at the neck but I have found that if you watch your handloading p's & q's, it is an easy cartridge to reload.
Have fun!
John