If he is seeking information regarding oil used in finishing stocks
https://www.vintageguns.co.uk/magazine/making-oils-for-stock-finishingVintage stock finishing
Thanks to M.D. Christian for the following:
"This was submitted to Handloader Magazine, Jul/Aug 1970 by Harvey A. Donaldson who said it was told to him by Frank Lefever, son of D.M. Lefever. He stated this was the method used in finishing stocks by Dan Lefever and other U S gunmakers and gunsmiths including Billinghurst, Brockway, Morgan James, and A.O. Zischang."
Place the stock in a sheet iron tank with enough linseed oil to cover stock. Stock was left for a day or so depending upon density of the walnut, a harder denser grain wood requiring longer than a more porous grain wood. Next was to remove the stock & stand to drain & leave for several days at least. Very Important: let stock dry completely; this first coat must be completely oxidized by the air before proceeding.
The next operation is to stop further penetration of the oil. It should have penetrated about 1/16" or so at this point, deeper of course in an open grain piece of wood than a closer grained one. Two formulas are given for this step depending upon wood density:
For the softer walnut: Take 4 oz. of boiled linseed oil & mix in 3 oz. of white shellac that has been cut in alcohol, 1 oz. Spar Varnish, 10 drops Venice Turpentine, 20 drops Oil of Cedar Leaves & enough Oil of Soluble Red to get the desired color. This was applied to the stock with a small wad of cloth & it would soon penetrate & sink into the wood & then be left to dry for 24hrs or more.
For hard close grained walnut: mix 1/2 pint of raw linseed oil, 3 oz. Spar Varnish, 1 oz. turpentine, 10 drops Venice Turpentine, & 1 grain Oil of Soluble Red. Apply this mixture & again allow to dry for several days.
(Soluble Red Oil is a dark reddish powder sold by some large drug stores or chemical supply houses. Only a very small amount is needed & he states a lump about the size of a match head will color a half pint of oil to a bright red. Some makers used Alkenet Root instead. Venice Turpentine was very thick, hard to pour, & used by old time violin makers.)
Apply a light coat of raw linseed oil with a rag or swab (some of the Red can be mixed in if desired) let stand for an hour or so, rub briskly with the palm of your hand for about 10 mins. Apply another thin coat of oil, but not enough to run or drip. Repeat this every 12-24 hours (when stock has absorbed oil & appears dull) for 4-5 treatments. Allow stock to stand for another couple of days, Apply another coat of oil & "Set it out of sight & forget about it".
After several days this coat will have hardened & gummed over the surface & appear about like a coat of varnish. Next coat the stock with hard auto cup grease, sprinkle with powdered pumice & take a wad of rags & scour off this coat down to the wood. Then rub finish with bare hand & let dry for a few more days & gun is ready for use. After this occasionally take up the stock & go over it with cup grease by hand & rub until dry. After the gun is used in hunting rub it over with raw oil until it is wiped dry.
If a super fine smooth finish is desired follow the pumice rubbing with fine powdered Rottenstone. Use this on a hard piece of felt held in the hand & rubbed across the grain.
If he is seeking instructions regarding oil finishing
https://doublegunshop.com/phiatt3.htm