The first,a and almost the only caliber for the Henry and 1866 was the.44 rf Henry Flat Apparently the last lot of 1866's was made in a .44 Henry cf. By a coincidence, the first large frame S & W was made in .44 Henry rf, but quickly changed to centerfire, the .44 American. By the way, the Turkish army used both the 1866 and the rimfire S&W in the original calibers.
In Cartridges of the World, the dimensions of both the Henry and S&W centerfire cartridges seem identical.
Except fot the Uberti "Yellow Boy", reproduction Henrys and 1866's started out in 44-40 wcf. I got my 1866 in .38 Spl for two reasons. First, I saw an original 1866 in .38 Spl., admitedly made up from factory parts in about 1918, but of original manufacture, as a special order. Secondly, I adopted the 1851 navy Richard Mason as my match guns, so the caliber fitted in, even though it is not actually correct.
Would not the .44 Russian, as the closest kin to the Henry cartridge be the most appropriate repro chambering? I see that someone does it in .44 Special, and claim that .44 Colt works just fine. Seems closer to the original.
Any thoughts?