If you have a gun and want to make it more durable, then you might want to put a protective coating on it. Then you won't be worried about how it holds up outside in the elements. If you plan to put one of these coatings on a firearm yourself, be sure to take these measures. Remove All Traces of Dirt and Oil Regardless of what coating you opt to install on a gun that you care about, you need to make sure the firearm is free of dirt and oil.