One thing I never see mentioned here, even by the most experienced, professional builders, is the oil dryers used by original longrifle and fine gun makers in their finishes.
There is a school of thought that many rifles may have been originally finished with varnishes. There are period recipes and descriptions of linseed oil boiling, both as a drying oil and as a step in varnish making. If not careful this approach can lead you down a rabbit hole of varnish-making (sometimes resulting in accidental linoleum making) and possibly into the heresy of luthery. . . . .
I have two oils on hand; the ingredients in both can be documented as being in use by workers in various woodworking trades during the 1750-1850 time period but usually as a step in the varnish-making process. My recipe "boils" the oil, and uses lead carbonate and aged spirits of turpentine as driers.
The base oil consists of
1 pint linseed oil (I usually get cold pressed flax seed oil at a drugstore--not because I think it is better but for repeatability)
5 teaspoons spirits of turpentine (thickened by exposing to air for a few weeks)
1 teaspoon lead carbonate
3 teaspoons Venice turpentine
Put the linseed oil, spirits of turpentine, and Venice turpentine in an enameled pot, and stir. Take out a couple of tablespoons and mull the lead carbonate into it, then add back to the pot. Slowly and carefully bring the contents of the pot to a simmer, and simmer for 10 minutes then remove from heat. Keep a lid for the pot handy in case it gets too hot and burst into flames. Let it cool to around 110-120 degrees F and filter it into a Mason jar through a piece of old T-shirt.
My other recipe is basically the same, except I use "red oil": raw linseed oil in which alkanet roots have soaked for a year or two (a couple months, shaken frequently, would be fine; I find it easier to just dump the roots and oil in a jar and let it sit in a cupboard til I need it). I'm still experimenting with this one.