I have done it. The problem is that the .44 Special cylinder is narrow. There isn't a lot of tolerance for increasing the bore by .01" near the head and increasing the rim by 0.017". I wound up having to tilt the reamer by a couple of degrees to keep the reamer from damaging the rachet.
It was way back when Slim was doing it (we are in the same club) and I forget how much of a cant I had to do. I wound up making a jig to hold the cylinder at the right angle, mounting the reamer in a drill press, and manually turning the reamer.
The .44 Special cylinder is spec'ed for a rim of .518+.012, the .45 Colt .516+.012, and the .44-40 .535+.012.