[Austin W Hogan]

Sean; Several years ago I recieved some
thoroughly rusted low number Springfields to restore for our local honor guard. I made a metal box and soaked the guns in kerosene for a month or two, which softened the rust. It is difficult to remove a Parker stock without opening the action. I would suggest that you find a container, perhaps a 4 or 6 inch pipe that will allow the barrel and frame to be immersed in kero, without submerging the stock. Remove the fore end, rest the muzzle in the bottom and fill with kero to 1/4 inch below the wood. You might try putting a little penetrating oil into the seams before immersion.
Does the lifter button move 1/2 inch? that is necessary to fully unlock the barrel.

A proper tap with a rubber mallet may do the trick, but a common rust bond between two metal pieces may be as strong as a weld. Softening the rust may prevent barrel metal from adhering to the frame, or the reverse, when separating the parts.

Best, Austin