I wouldn't go near a '73 action in .44 Magnum.
They make and sell gobs of them in .357 Mag whose chamber pressures are practically identical to those of the .44 Mag. So if it's safe in .357 why would it not be in .44?
I've run across a couple of these:
UBERTI 1873 CARBINE 19" 44 MAG Uberti 1873 Carbine 19" .44 Mag Blue Came REAL close to buying one, but a .44 Special came along instead.