Any update on removing barreled action from stock?
If it's a factory stock it will have two factory cross bolts. Also, if it is an all factory rifle it will have two recoil lugs. One in front of primary action pad and one on barrel. It would be rare that a factory wood stock that probably dates between early 90s and 2006 would swell to bind action. If anything, the older the stock, the looser it gets as wood has a tendency to shrink as it ages. The only exception is if it lived most of its life in dry climate then recently moved to a very humid environment where it could temporarily swell and bind. The advice about putting in the freezer is a good one and is a trick used by those who occasionally do glass bedding jobs that get hard to separate. I if do these jobs in the winter time, it is plenty cold outside for the purpose.
The other thought I had was the possibility a previous owner tried to glass bed the thing and got it stuck?? Then for certain freeze it then, with some judicious kinetic force, try to remove the stock. Try placing top edge of butt on bench with barreled action above a pad... like a few layers of blanket. Hold the rifle upside down while holding the forehead of the stock. Whack the barrel with a wood block like a 2x4. If it comes out you want the barreled action to land on the pad. If it "pops" just a little loose... that starts the process. Keep see-sawing it back and forth to complete the removal.
If you glass bed it, do the action side first. When satisfied with that, then bed the bottom metal side.
Without inspecting the hairline crack, hard to tell if it would even be worth doing anything with it. By glass bedding both sides of that internal stock web, top and bottom, in addition to the cross bolts already in front of and behind that web, may not be required at all. Good luck!