Fitting a .22 barrel on a .177 action will result in an over-power gun.
You'll need to de-tune it so that it runs about 10fltb in .177 to give you high 11's in .22
To me the resulting loss in velocity of the .177 defeats the point of having the .177 in the first place.
Not to mention the faff of changing over and the uneven wear on the breech jaws vs the two breech blocks which will affect the lock up and accuracy.
I'd give it a miss (pun intended)