Once a pistol, always a pistol....you won't be able to de-restrict it, and it will be considered a pistol in this country.
It may be easier to try and import just the barrels.
It would be interesting to see if this can come to fruition.....are you planning on an attempt?
Buy a non-restricted 10/22 and buy a Charger. Take the Charger barrel off and mount it on the non-restricted 10/22 receiver and with a full stock (stock mods necessary I imagine).....voila.....non restricted with 10" barrel.