I’m with Ted.
If you have ever sprayed a mechanism with WD-40, you will see after a time it dries to a sticky waxy substance.
That’s exactly the opposite of what you want inside of a shotgun action that is probably starting to show some wear.
I might use WD-40 as a water displacer on a duck gun but not when it’s cold.
If you are up to it, carefully take the stock off and clean the action with a can of brake clean, let it dry, and then lightly oil, the pivot points with a proper machine oil.
When you crack it open, you will probably be quite surprised at how much crap blows back through the firing pin holes.
