To clean a shotgun, unload it and check the chamber, the carrier and the magazine tube, take the barrel off if your gun is built for it, scrub the bore and chamber with solvent and patches, clean the action and the receiver tracks, add a few drops of light oil, and put the barrel back on and check it is seated. Mossberg says a routine cleaning needs no more taking apart than that.
This guide follows Mossberg’s owner’s manual for the 500 and 590 pump action shotguns, which has a full cleaning and lubrication section. Other makers and other types, such as semi-autos and over-and-unders, come apart differently, so read your own manual and follow it where it differs. The cleaning ideas carry over. The takedown steps may not.
What You Need
Mossberg tells owners to follow the instructions and equipment that come with a quality gun cleaning kit. For a shotgun that means a bore brush and patches sized for your gauge, solvent, light oil, a rag and a soft brush. Mossberg says a stiff brass bristle brush is useful for stubborn deposits in the bore. It also says never to use a brush with metal bristles on the receiver or the trigger housing, because it can remove the protective coating. See our post on what goes in a gun cleaning kit for the basics.
Wear eye protection. Mossberg says to protect your eyes from oil splatter and spring loaded parts during cleaning.
Make It Safe: Unload and Check Three Places
On a shotgun, an empty chamber is not enough. Mossberg says to put the safety fully rearward, in the ON (SAFE) position, and to visually and physically check the chamber, the elevator and the magazine tube before cleaning. The shells live in the tube under the barrel, so a gun can look empty while holding rounds.
Mossberg’s steps to unload a pump: close the action without a shell being chambered, turn the gun so the trigger guard faces up while keeping it pointed in a safe direction, and push the cartridge stop on the right side with your thumb to release the shells from the magazine tube one at a time. Then press the action lock lever, pull the forearm fully back, and check the chamber, elevator and tube again. The NRA’s gun safety rules say to keep a gun unloaded until you are ready to use it.
Take the Barrel Off and Clean It
Most cleaning happens on the barrel, and on a pump it comes off the receiver. Mossberg’s manual shows two ways. On a 500, a takedown screw holds the barrel. On a 590, the magazine cap does, and you unscrew it. Both begin by pressing the action lock lever and moving the forearm back until the front of the bolt sits in the middle of the ejection port. The manual says never to close the action or pull the trigger while the barrel is removed, because it could damage the gun.
Once the barrel is off, Mossberg says to scrub the bore and chamber with solvent, then follow with cleaning patches until the barrel is clean. Finish with a lightly oiled patch for a protective coat. Be careful here: Mossberg warns that patches or too much oil or grease left in the bore can cause a dangerous obstruction, and obstructions can damage the gun and cause serious injury or death. Look through the barrel before you put it back, and check that it is clear. The manual says to check the chamber and bore for obstructions, excess oil or grease before you shoot, too.
Clean the Action and the Receiver
Mossberg’s manual covers three more areas:
- The action. Clean all parts of the action, including the bolt, the bolt slide and the action slide bars, to remove built up residue. Use an evaporating solvent. Action parts stay cleaner longer if you use lubricant sparingly.
- The receiver. Clean the inside with a rag or a soft brush, with special attention to the tracks that guide the bolt and the bolt slide. When the tracks are clean, put a few drops of light oil in them. Take care with the outside to avoid cosmetic damage.
- The trigger housing. Brush loose residue from it with a soft bristle brush. The manual says the trigger housing is a complex assembly that should not be taken apart for routine work. It also says not to pull the trigger and let the hammer fall while the housing is out of the receiver, which can cause injury or damage.
That last point matters most. Mossberg says field disassembly is complete once the action parts come out, and that further disassembly should be done only by an authorized service center or a qualified gunsmith. For a routine cleaning, you have no reason to go further.
Oil Lightly and Put It Back Together
Mossberg says normal use needs only a light oiling of inside and outside metal surfaces to prevent rust, and very little lubrication beyond that. In cold weather, it says to avoid over-lubrication, because many lubricants thicken in low temperatures and can slow the gun.
When you reassemble, follow the manual for your model. On Mossberg’s 500, the barrel goes back on with the takedown screw tightened finger tight only, and on the 590, the magazine cap is finger tight only. The manual says not to use pliers or a wrench. Then look through the ejection port to check the barrel is fully seated, with the barrel extension resting firmly against the shoulder in the top of the receiver. If you cannot clear an obstruction from the bore, Mossberg says to take the gun to a qualified gunsmith.
How Often, Storage and When to Hand It Off
Mossberg recommends a thorough cleaning after every 200 rounds. It says dusty, dirty or harsh weather, or ammunition that leaves a lot of powder residue, may call for cleaning more often, and that you should clean the gun as soon as possible after use, especially if it has been exposed to moisture. For more on timing, see how often to clean your gun.
For long storage, Mossberg says to clean and oil the gun first, not to plug the barrel, and not to store it in a fabric-lined case that will absorb oil and leave the metal open to corrosion. If rust has already started, our post on whether a rusty gun can be restored explains what a cleaning can and cannot do.
If you would rather skip the job, Lakeside cleans guns in our shop in Cumming for $35, or $25 if you bought the gun from us. Surface rust cleanup is included during a cleaning, to the best of our ability. Gunsmithing is walk-in. Our posted prices are for a gun in factory condition, so a gun with other changes gets looked at first. Ask the counter about your shotgun, and see what a professional cleaning includes and the gunsmithing price list. Or send us a question through the contact page.
