Just to make you squirm;
The U. S. Department of Agriculture Circular No. 128, October, 1930, Effectiveness of Moisture-Excluding Coatings on Wood, described work done at Forest Products Laboratory beginning in 1914. Their conclusion then, and in all their subsequent work, was that while some treatments slowed the dimensional changes of wood as it absorbed water “...an oil coating had little effect.” The 1930 Bulletin described work after World War I that included coatings of five coats of oil plus two coatings of floor wax and, also, soaking wood in oils. They also tested the complete range of paints, enamels, and coatings available at the time. They had their best results with aluminum paints and some varnishes. Again they concluded, “Coatings or treatments with oils, floor wax, and the like were low in effectiveness.”

Research Paper 462, December, 1985. Results reported include treating wood with oils and oils dissolved in mineral spirits. In both cases, the treated wood absorbed more water in a high humidity (90%) chamber than did untreated wood.

I don't think oil is a waterproofer and never did. Many old boats relied on moisture to effectively swell their planks and seal them up so they wouldn't leak. The oil allows the wood to breath and allows an escape route for moisture to air dry. I had a fiberglass sailboat that had teak decks and teak seats in the cockpit and teak oil is the only oil I've used on a boat. Not to waterseal or waterproof it but to beautify it after sitting in the Arizona sun it would turn gray and the teak oil would only brighten it up. Show me proof otherwise. Epoxy is the very best waterproofing but who wants to epoxy a stock?

Suz
or
U
snooze

heck if you tested my .270 stock for whats gone into her over the years...tong-teak-30/40-diesel motor oil- breakfree-blood-mud-more than a bit of my sweat (and tears) 3n1 sewing machine oil-2stroke oil
and she still looks ok and does the job it was designed to do
snow bashing and using her for a walking stick in snow is by far the hardest on stock finish.

In order to keep water and water vapor out of any wood product it must be sealed. In order for a penetrating sealer (the best kind for stocks) to work the wood has to be dried to about half the moisture content that it has after kiln drying (15% is the maximum moisture content for reliable sealing) Penetrating sealers vary in composition but most use a hardening agent much like an oil based urathane. The penetrating epoxies are by far the most protective and can be repaired if scratched.
There is no amount of linseed oil or tongue oil that will seal a stock. They can give a very nice appearance and last for years with easy touchups but they do not seal the wood from moisture. Tru-oil has a polimer sealer built in to the oil and when properly applied will seal the wood. Penetrating poly urathane is a good, inexpensive sealer that can be applied over oil based stains and give any desired appearance from satin to high gloss.
I'm with Suz on this one.

I made the assumption aesthetics was the goal. A two part poly finish will seal wood from moisture but it won't give the type of deep rich finish a quality stock deserves. I read ypur reference Sue. I have also spent hours burnishing walnut and cherry using canvas and leather. Water beads on the surface of the wood because the surface has been completely sealed. The surface is shiny and hard because all the fibres have been pressed diwn and all surface pores filled. I prefer this look to the plastic appearance of modern sealers.