What is the best method to keep a firearm from rusting?

Keeping a firearm dry, clean, and lightly oiled is the best method to prevent rusting. Moisture is a primary factor that contributes to rust formation, as it reacts with the metal surfaces of the firearm. By maintaining a dry environment and ensuring the firearm is clean, you reduce the chance of moisture and contaminants, such as dirt or salt, which can promote corrosion.

Applying a light coat of oil creates a protective barrier on the metal surfaces, further preventing moisture from coming into direct contact with the metal. This oil film acts as a shield against environmental factors that could lead to rust. Regular cleaning and maintenance of the firearm with appropriate oils not only helps in preventing rust but also enhances the overall functionality and longevity of the firearm.

While leaving a firearm in its case may offer some protection, if the case is not moisture-proof, it may inadvertently trap moisture inside, leading to rust. Using a rust-resistant cover can provide some level of protection, but it may not be as effective as a proper cleaning and oiling routine. Storing a firearm in a wet environment is detrimental and would significantly increase the likelihood of rusting. Thus, the practice of keeping a firearm dry, clean, and lightly oiled is the most comprehensive approach to rust prevention.