The Mossberg 500 series shotguns are a pump-action design chambered in either 12- or 20-gauge. As with any firearm, keeping it clean and lubricated aids safety, reliability and prevents corrosion. Lubrication is necessary to keep the action parts moving smoothly. The Mossberg 500 requires a light coat of gun oil on certain parts, though care must be taken to not over-lubricate. Too much oil will attract dirt and dust, gumming up the action and impeding reliability. Lubrication is best done after the gun has been field-stripped and the bore, chamber and action parts, such as the bolt and action bars, have been cleaned.
Gun oil
Lint-free rag
Gun cleaning kit
Patches
Place a patch in the cleaning rod jag. Add a few drops of oil to the patch, then run the patch through the barrel to coat the inside of the barrel with a thin layer of oil.
Drop a few drops of oil onto the bolt and bolt face, then spread it around with your finger tips. Use the lint-free rag to wipe up excess oil.
Place a few drops of oil on the action bars. Spread the oil with your fingers, then use the lint-free rag to wipe up the excess.
Wipe the inside of the receiver with an oiled lint-free rag. Place a few drops of oil in the slide action bar channels.
Re-assemble the gun, then wipe the exterior metal surfaces with an oiled lint-free rag.