Yep unfortunate, the .44 Special is the successor to the .44 Russian. And the .44-40, well... no interest other than a bunch of yuppies have their repro Winchester ‘73’s chambered for it.
If the cylinder is long enough I might bet Bowen to rechamber one. Pricey, but why not?
LOL...actually, for a long time, that was probably the best dual-use carbine/revolver combo out there. Of course, now that there's a .45-70 revolver, all bets are off ;-)