Place the barrel and receiver in freezer for about 30min or more, until the entire mechanism is at zero degrees. Remove from freezer and place barrel in padded vice, apply hot air via hot hair dryer to receiver near barrel to heat and expand receiver. The 10/22 receiver is aluminum which is a better heat conductor than the steel barrel. The receiver should heat faster and expand with the heat while the barrel remains cold and does not expand as much. With gloved hands, pull on the receiver to loosen it and to slide it off the barrel. Applying a bit of penetrating oil before freezing may help. Repeat if necessary.
best, nrb