Linseed oil, also known as "flax seed oil" is a clear to yellowish drying oil obtained from the dried ripe seeds of the flax plant (Linum usitatissimum, Linaceae) by cold pressing, followed by an optional stage of solvent extraction.
Linseed oil contains the triglycerides of five unsaturated fatty acids, palmitic acid (about 7%), stearic acid (3.4-4.6%), oleic acid (18.5-22.6%), linoleic acid (14.2-17%) and the omega-3 fatty acid α-linolenic acid (51.9-55.2%).[1]
In common with other polyunsaturated drying oils, linseed oil oxidises when exposed to air, undergoing polymerization reactions which convert a liquid layer to a solid film. Consequently, linseed oil is used on its own or blended with other drying oils, resins and solvents as an impregnator and varnish in wood finishing, as a pigment binder in oil paints, as a plasticizer and hardener in putty and in the manufacture of linoleum. The polymerization reaction is exothermic, and can cause a large, compact mass of rags soaked in linseed oil to ignite spontaneously.
Linseed oil is an edible oil, but because of its strong flavor and odor is only a minor constituent of human nutrition, although it is marketed as a nutritional supplement.
It was used on riflestocks for a very long time, has suffered a lot of bad press that it probably doesn't deserve. I have at least six rifles with raw linseed oil finished stocks and have used them for forty years or so.The bad news is that they sweat in the sun for the first four or five years and being a saturation system it adds weight. The good part is that it doesn't appear to allow much instability in changing humidity, and is easily renewed. If you take the rifle out for a long time in very wet conditions, the surface finish may be damaged but the oil is still in the wood and the stock seems to stay stable. That's why the military has used it for a couple hundred years. It may be that there are more modern finishes that are easier to apply and may be as good or better, but raw linseed oil is far from useless.
Grouch
It does go rancid and you would probably end up with a stink problem ( would you rub sardine oil on a gun stock)
Flax seed oil will go rancid in time... not sure if boiling it would stabilize it or not, but it can't hurt to try I guess.
my health minded daughter is visiting with her family and bought an expensive bottle of raw flax seed oil but it tastes like cod liver and nobody will take it.
Can I put it on gun stocks or should I boil it first?
Or fence posts?