[The 39 action is too short for the 22 WMRF cartridge.]
[However, if they would increase the size of the action proportionately, to the size of the 22 WMRF cartridge,]
No, it's long enough.
Granted, the internals need repositioning/reshaping, and the mag throat bored wider with an attendant wider mag tube/guides/etc, but..........
If I were re-engineering a gun in stainless, I'd sure look at some internal alterations, as well.
As a retired Mechanical Design Engineer, I think the action is too short to be used, as is, for the 22 Magnum... Then, there are strength of material issues to consider.
Bill
