Can you open the crack a bit by flexing the stock? How deep does the crack go with the action removed?

If it is a deep crack, more than 1/2" down from the surface drill out from the inside of the stock from the back of the action towards the wrist and use a threaded screw with acraglas or similiar viscosity epoxy to repair it. If it is not a deep crack get is as open as possible and allow the araglas to penetrate as deep as possible and allow to cure. Wipe an excess acraglas before it sets and you should have a repaired crack that is almost invisible with no refinishing required.

Hunt hard, kill clean, waste nothing and offer no apologies.

"In rifle work, group size is of some interest...but it is well to remember that a rifleman does not shoot groups, he shoots shots." Jeff Cooper