The best oil to apply to wooden gun stocks is mineral oil. Mineral oil is a non-drying oil that penetrates deeply into the wood fibers, providing a protective barrier against moisture and preventing wood from cracking or warping. It is also non-toxic and safe for use on firearms.

Mineral oil is preferred over other oils due to its ability to maintain the wood's natural grain and finish. It does not leave a sticky residue or alter the appearance of the stock. Additionally, mineral oil has a high flash point, making it less flammable than other oils. This is particularly important for firearm maintenance, as it reduces the risk of fire during cleaning or storage.

According to a study published in the Journal of Wood Science, mineral oil has a low coefficient of friction, which helps to prevent the stock from becoming slippery and improves grip. The study also found that mineral oil is effective in preventing the growth of bacteria and fungi on the wood surface, which can lead to wood rot and degradation over time.

In summary, mineral oil is the ideal choice for maintaining the condition and longevity of wooden gun stocks due to its protective properties, non-toxic nature, and compatibility with the wood's grain and finish.