How to Clean a Shotgun:
A Guide for 12, 20, and 28 Gauge Firearms

A practical routine for break-action, pump-action, and semi-automatic shotguns

A gauge-matched bore tool and a model-specific maintenance routine are the foundation of safe shotgun cleaning.

To clean a shotgun, unload it completely, follow the owner’s manual, field strip only as directed, and clean the chamber and bore from the breech whenever possible. Then clean the accessible action surfaces, service the choke tubes as the manual specifies, lubricate lightly, and complete an unloaded function check.

The barrel routine is similar across 12, 20, and 28 gauge shotguns. Match the bore tool to the gauge, and match disassembly to the shotgun’s action type.

Before Cleaning: Unload and Verify Every Shell Location

The NSSF safety rules call for opening the action and confirming that the chamber and magazine are empty. Wear eye protection, provide ventilation, follow every solvent warning, and keep ammunition away until the shotgun is fully reassembled and inspected.

What You Need to Clean a Shotgun

1.    The owner’s manual for the exact shotgun model

2.    A protected work surface, eye protection, lint-free cloths, and a parts tray

3.    A gauge-matched Bore-tip, shotgun rod, bore guide if applicable, and a compatible bronze or nylon brush

4.    Firearm solvent and lubricant approved for the shotgun’s finishes and materials

5.    A nylon utility brush, foam detail swabs, and the correct choke-tube wrench

For owners who maintain more than one gauge, the 12ga/20ga/28ga Shotgun Firearm Cleaning Kit (SKU 87-9903) includes 12, 20, and 28 gauge/.50 caliber Bore-tips plus nine Gun-tips™ for accessible action surfaces. The Bore-tips attach to a standard 5/16-27 shotgun rod; pair the kit with a compatible rod.

The 87-9903 shotgun kit combines gauge-specific Bore-tips for 12, 20, and 28 gauge bores with Gun-tips for accessible action surfaces.

Choose the Correct Bore-tip for the Gauge

Do not substitute a nearby size. A correct fit gives the foam controlled contact without forcing the tool through the bore. The three shotgun sizes use standard 5/16-27 shotgun-rod threading:

• 12 Gauge Bore-tips®: SKU 41-0012 for 12 gauge barrels.
• 20 Gauge Bore-tips®: SKU 41-0020 for 20 gauge barrels.
• 28 Gauge/.50cal Bore-tips®: SKU 41-0050 for 28 gauge barrels.

Step 1: Field Strip Only as the Manual Directs

A break action may separate into barrels, forearm, and receiver. A pump often requires barrel removal for thorough access. Semi-automatics vary: gas and inertia systems have different parts and lubrication points. Stop at the maintenance level in the manual. Do not remove the trigger group, magazine spring, gas parts, or bolt unless instructed.

Manufacturer instructions show why a generic disassembly sequence is risky. The Browning Citori manual covers a break-action shotgun, the Browning Maxus II manual has separate gas-system directions, and the Mossberg pump-action manual follows another. Use the manual for the firearm on your bench.

Gauge determines bore-tool size, but action design determines how the shotgun is opened, field stripped, and cleaned.

Step 2: Clean the Chamber and Bore

Start at the breech whenever the design allows. Apply a small amount of approved solvent to the correct Bore-tip and make a full pass through the barrel. Follow the product label’s dwell time. If the manual permits brushing, use a gauge-matched brush and push it fully through before reversing direction. Follow with a Bore-tip, blot the foam on a cloth, and repeat until little new residue appears. Finish with a clean, dry tip. The Bore-tips.com use-and-clean guide explains how to blot, wash, dry, and reuse the foam tips.

Inspect the chamber, forcing cone, bore, and area just behind the muzzle. Shot cups can leave plastic streaks, while powder and lead residue may collect near the chamber and choke. Clean both barrels and chambers on a side-by-side or over-and-under. If the barrel is ported, use only the method approved by the manufacturer.

Step 3: Clean the Action and Accessible Working Surfaces

Begin dry with a nylon brush, cloth, or lint-free foam swab. On a break action, wipe the breech face, extractor or ejector area, barrel lugs, hinge surfaces, and forearm contact points that the manual identifies. On a pump, clean the accessible bolt, receiver rails, carrier, and action-bar areas. On a semi-auto, clean the bolt and receiver, then service the gas or inertia components only as the manual directs. Keep excess liquid out of the firing-pin channel, trigger group, and stock.

A lint-free foam detail swab can lift residue from the accessible extractor and breech area without leaving cotton fibers.

Step 4: Service the Choke Tubes Carefully

Follow the choke instructions for the exact barrel and tube system. Some manuals direct the owner to leave the choke installed during bore cleaning so residue does not pack into the barrel threads. After the bore is clean and the shotgun is still unloaded, remove the tube with the correct wrench if the manual calls for service. Clean the tube and barrel threads, apply only the specified light oil or choke lubricant, and reinstall the correct gauge and choke system securely. Never mix choke systems that look similar.

Step 5: Lubricate Sparingly

Apply lubricant only at the points and in the quantities shown in the manual. Break actions may require a thin film on specified hinge and locking surfaces. Pumps and semi-autos have different rails, action parts, and gas components. Excess oil collects residue, can migrate into wood, and may interfere with reliable operation. Wipe away visible excess.

Step 6: Reassemble and Perform an Unloaded Check

Reassemble in the manual’s order. With ammunition still outside the room, inspect every bore and chamber for obstructions, forgotten swabs, or loose parts. Confirm that the choke tube is correctly seated. Perform only the unloaded function check specified by the manufacturer. If the action, safety, extractor, ejector, carrier, or bolt does not operate normally, stop and review the assembly or consult a qualified gunsmith.

How the Routine Changes by Shotgun Type

• Break action: clean every chamber and bore, then attend to the breech face, extractor or ejector, hinge, locking surfaces, and forearm contact points named in the manual.
• Pump action: clean the chamber and bore, then wipe the bolt, carrier, receiver rails, and action bars that are accessible at the approved field-strip level.
• Semi-automatic: clean the barrel, chamber, bolt, and receiver, then follow the model-specific procedure for its gas or inertia system. Do not copy a gas-gun routine onto an inertia gun.

How Often Should You Clean a Shotgun?

A sensible baseline is after each day of shooting, with immediate attention after rain, salt air, mud, dust, or long-term storage. High-volume clay shooting may leave more plastic and powder residue, while a semi-auto can need action or gas-system service sooner than a break action. Use changes in cycling, extraction, or visible fouling as a reason to inspect and clean, not as a reason to keep shooting.

Common Shotgun Cleaning Mistakes

• Removing shells from the chamber but leaving shells in the magazine tube
• Using a 12 gauge tool in a 20 or 28 gauge bore
• Following the wrong action-type disassembly or lubrication routine
• Ignoring the chamber, forcing cone, choke tube, or choke threads
• Using too much solvent or oil around the trigger group, firing-pin channel, or stock
• Leaving a patch, swab, brush, or loose choke tube in the barrel

Build a Routine Around the Shotgun You Own

Good shotgun maintenance is simple when the safety check, gauge-matched tools, action-specific manual, and restrained lubrication stay consistent. Clean the chamber and bore, address the working surfaces your manual identifies, and verify the firearm before storage or use. Browse the shotgun cleaning collection on Bore-tips.com for 12, 20, and 28 gauge options.