What type of lubricant is described as non-penetrating and used on firearms?

• A. WD-40
• B. Penetrating oil
• C. Gun oil (non-penetrating)
• D. Water

Answer: (C)

Non-penetrating gun oil forms a protective film on firearm metal surfaces to reduce friction between moving parts and to help prevent rust. This type of lubricant stays on the surface rather than seeping into tight passages, making it ideal for regular maintenance and reliable operation. In contrast, penetrating oil is designed to creep into small gaps to loosen stuck parts, not to provide long-lasting surface lubrication. WD-40 is mainly a cleaner and moisture-displacer, and while it can offer temporary lubrication, it isn’t the best long-term firearm lubricant. Water obviously isn’t a lubricant. So the best fit for a non-penetrating, everyday firearm lubricant is gun oil.