I recently got an X-Bolt medallion maple. Took the stock off to change the trigger spring and noticed that the inside of the stock looks like bare wood. I could be wrong, but what is the best product and/or way to seal it up? This rifle will be used in most weather conditions other than pouring rain.

That is usually my first effort with stock finishing, and my approach is to thin (turpentine/mineral spirits) whatever finish that's going on the outer surfaces by about 30% and applying 3 or 4 coats to the rough inner portions. Typically allow a day or two of curing between applications. I'm mostly an oil fan using Tru or Tung oil. Some around here like maybe Sitka might suggest an epoxy. I've never gone that route as I've not researched the thinner longer curing varieties that might do a better job of soaking in. Those might be a good option as well if one's working our western coastal regions with 200+ inches of precip.

Might check beneath the butt plate and potential sling stud holes as well.

Edited: A little surfing reveals there are some resins out there exhibiting up to a 6-hour pot life. Days, however, for them to cure to a sanding stage.

What about a spar varnish or urethane? Even some BC sealer? I think those would all provide some adequate protection

Literally, any topcoat would work. Some of them would benefit from thinning, others not. Oil based topcoats / finishes will dry slower than their water based brothers and sisters. If you have any TruOil laying around you can thin that 10% by volume and wipe it on with a rag. VM&P Naptha will make it dry faster than Mineral Spirits. You can use the same method with nearly any oil based finish you have laying around. Don't get wrapped up in the Urethan vs. Polyurethane mind game. Polyurethane is just boiled urethane anyway. A spar varnish would work as well, but don't attach too much value to the word spar. It's nearly meaningless for your application.

Modern spar varnish is generally a combination of urethane and organic oil, these days usually tung.

As Sniggly notes, urethane and polyurethane are pretty much the same deal. Either works fine.

Some people believe a thin layer of epoxy works best of all, but Browning tried that back in the "salt wood" era (when they and few other companies got a bunch of walnut "cured" in salt to speed up the drying process--which of course rusted firearms. Epoxy didn't entirely prevent the rusting, but if you just want to do a basic weather-seal a thin layer would work.

Arrow wood finish is good stuff

Tru oil, hand rubbed is pretty hard to beat.

thompsons water seal.

I've done several rifles interiors using epoxy, per JB - in the past. It works - and in fact just today finished doing the same to two his/hers stocks for the same rife, using Brownell's Accragas. Should be cured enough by Sunday to continue the outside with True-oil. Mind you, these are beater stocks, not show pieces.

5-minute epoxy might even work - dunno. I prefer a bit more "soak-in" time. Also wise to do the end-grain under the butt pad.

It darkens wood but the best way to preserve wood from weather and water is pinetar treatment. It's pinetar heated and cut with turpentine mineral spirits and your can also ad ik some boiled linseed oil. Heat is your friend and it sinks it into the wood.

Lots and lots of options and lots and lots of Voodoo out there. Simplest thing to realize is that the outside finish should match the inside. Otherwise one will transfer water differently from the other. If there is a serious imbalance the wood will start walking.

Sealing the interior while applying the initial finish is obviously a lot easier. Spar urethane is usually oil based and will transfer atmospheric water faster than bare wood. Tru-oil is in the same boat.

Essentially epoxy and cyanoacrylate are the only truly waterproof finishes. But again, is that what you really want?

Thinning does not do anything for penetration. It does make application easier. It is very easy to test.

Actually, Browning bought the process from Morton and salted their own walnut.

I do a several coats of tung and finish up with a coat or two of minwax wipeon satin ply.

I do not do a lot of refinishing, but the ones that I have done, were great with tung oil.

Tung oil is about as tough as sealer gets.

Pure tung oil is exactly as good as linseed oil. Virtually no difference and both allow atmospheric water in or out faster than bare wood.

My contention remains that matching.the exterior finish in the barrel channel allows water to be transferred rqually throughout. Thereby helping to stablize the stock.

Very useful. I've got a few stocks finished with linseed oil, inside and out, and in constantly wet conditions they seem as stable as the urethane finishes. Now that I think about it, the stocks I've had that walked were usually ones where I'd hogged out the barrel channel and sealed it with something different from the exterior finish. Thanks.

Does anyone apply paste wax at any time?

This^^^…..Spar Urethane is readily available and easy to use. It’s specifically made for exterior use, is more water resistant than most other types of clear finishes, and more flexible than many epoxies or polyurethanes. It also has UV inhibitors ( but that’s not much of a concern with stocks).

SitkaDeer - as a matter of friendly discussion I am skeptical of your first claim. The dimensional stability of any given species is, for the most part, a known data point, since we've had time to find and categorize by that particular data point for some time now. Essentially, bare wood of any species will have a given hygroscopic rate of transfer, and a major factor of influence would be whether or not that species was open celled or closed celled (i.e. White Oak vs. Red Oak). We know that plasticized resins are hygroscopic prior to cure, and less hygroscopic post cure, otherwise there'd by no reason at all to put a finish on a dinner table. Same with exothermic curing oils (or drying oils - I don't filet people for using either term). So, in summary, to apply any finish at all, realizes an advantage in the protection or reduction of wood movement, since a film or barrier of a sort is being placed over the wood.

Your contention that matching exterior finishes is a point on which I agree. But, I suspect that Mach3 won't know what that is unless he calls the maker and asks what that finish is, and if they are anything like furniture manufacturers, he might get the iron curtain treatment. I won't claim that I know what the finish is on his stock, but I am of the opinion that since he is addressing a post manufacturing issue, that whatever is most available to him might be good enough.

Now you tell me.

And that makes sense.

Dammit, Art, why can't you be more timely?

It seemed like a good idea at the time, tho, and hasn't really caused me any problems that I know of. But I bow to your experience.

Yes, lots!!!

Excellent points, well made, especially the final point. However, there are few woods commonly used for stocks which reduces the range of data points considerably and I should have been more clear about that.

That said, emperical testing is fun and easy. Once upon a time I made ridiculous numbers of test cubes with different finishes and tracked their weights over time and humidity changes. I stand by the fact oils, even when cured, suck up water vapor faster than bare walnut, maple, beech, and cherry.

A long thin strip with oil on one side and poly on the other will bend as relative humidity changes. Thank you for your clarity and comments.

Appreciate the explanation. I've run into the wood movement problem in certain types of furniture, humidors, and custom acoustic guitar making (specifically in the bracewood for the tops and wood(s) used in the necks.) I'll send you a pm with some more questions regarding your test cubes. Don't wanna hijack Mach's post with drivel he doesn't need, and with other questions most others besides us...wouldn't care about anyway.