If protection from gun oil is the only goal, then the crazy glues, varnishes, etc. will all work OK. But if we want to also repair or prevent cracking and splitting in the stock head or inletting, I still prefer a good penetrating epoxy for this type of work. Cyanoacrylate glue is very strong in tension, but not very strong in shear. Remember the guy on the TV commercials who hung from his hard hat after gluing it to an overhead I-beam with a drop of Crazy Glue? If you smacked it sideways, it would have snapped right off. I have no doubt that it will help stabilize soft punky wood and also repair small cracks, but it is more brittle than wood stabilized or repaired with epoxy. The same can be said for the polycarbonate wood stabilizers such as Minwax Wood Hardener. It may be fine for doing a repair on a rotted door frame or window sill, but a good penetrating epoxy will outperform it for sealing and providing strength under the pounding and twisting forces generated in a gun stock under recoil.
You'd also have to be pretty damn slow to ever glue your fingers together with an epoxy. But that may be why Ed Good hasn't made a reply. Any of these products can and will interfere with the penetration of stain and stock finishes, so care must be taken to keep any off of exterior surfaces during application.
