Ixnay on water based stains (they can raise the grain unexpectedly) and oil based stains from the hardware store (they tend to muddy the wood figure and don't penetrate very well and are prone to UV light degredation). For my money there is no better coloring agent (if I were to color a piece of walnut in the first place) than analine dye, formulated with alcohol-- penetrates well, doesn't raise the grain, and the color really "pops" when finish applied over top of it and stays that way (highly resistant to UV light degredation).
Linseed oil is at the bottom of the list for wood finishes- it provides about zero protection. That, and any of the proprietary "oil finishes" sold to unsuspecting folks under the guise of "gun stock finishes" would be my last pick. Unfortunately, many factory and military stocks were finished with oil and therein lies its best reason for use in refinishing- to restore a factory finish. Why did the factories/arsenals use oil? Because it was/is quick and cheap, not because it's the very best possible finish. At the very least, wax the bejesus out of it when done so as to provide a modicum of protection against water fenestration.
What exactly does your stock look like at this stage? Pics would be an enormous help. I assume the wood is walnut? If it is splotchy after stripping and initial sanding, I would submerge it in acetone for nigh onto a week to try and leech out any agents present in the wood that are making it splotchy, and then re-evaluate. (And post pics!)
Barrier finishes are ever the best, especially on guns that expect to see inclement conditions in the field. Matte or semi-gloss finishes are to be avoided though- they are created by adding microscopically ground silica to the varnish and as such are far less resistant to UV light degradation- the real killer of all finishes. Best to use gloss anything, and rub it out when done to achieve a "soft" look.
Last edited by gnoahhh; 02/04/16.
