How to Prevent Gun Rust During Long-Term Storage

For a firearm that will sit unused for months, prepare the metal for storage and decide when you’ll inspect it. The preservation procedure may be different from the lubrication used between range trips. SIG Sauer’s P365 manual, for example, specifies additional preparation for storage lasting 90 days or longer. [1]

Clean it after its last use

Completely unload the firearm and verify that the chamber is empty before beginning. Clean it using the procedure for that model, including the areas normally reached during its prescribed field stripping. Let any moisture introduced during cleaning dry before applying the storage preservative.

A firearm that hasn’t been fired may still need cleaning. GLOCK calls for cleaning and lubrication after exposure to perspiration. Carrying a pistol can leave contamination on the metal without putting another round through it. [2]

Pay attention to surfaces that have been handled since the last cleaning. Fingerprints and perspiration can leave salts that promote corrosion. Once the metal has been prepared for storage, minimize direct handling of those surfaces. [3]

Give wet equipment time to dry separately. Browning advises removing firearms from their cases after hunting or shooting. A dry-looking gun can otherwise end up resting against padding that still holds moisture. [4]

Use the preservation procedure intended for the firearm

Browning recommends a very light coat of gun oil followed by a thorough wipe-down. Ruger’s AR-556 manual describes wiping cleaned surfaces with a very lightly oiled patch or cloth. [4, 5]

SIG’s P365 procedure for storage of 90 days or longer combines heavier preservative application with barrier packaging. [1] Our long-term pistol-storage guide explains that model-specific procedure and the areas kept free of lubricant.

With a wood-stocked firearm, consider where excess oil can run during storage. Browning recommends horizontal storage where possible to keep oil from migrating into the buttstock and softening the wood. [4]

Choose storage materials that will stay dry

A case used to transport a firearm isn’t automatically suitable for leaving it unattended for months. Browning warns about condensation in tightly sealed cases. Ruger’s AR-556 manual advises against storage in a leather case or scabbard because leather attracts moisture even when it appears dry. [4, 5]

Inspect the material that will touch the gun before putting it away. Dry damp padding separately and replace padding that is deteriorating. Our foam-lined case guide explains what to look for. If the firearm’s preservation procedure calls for a barrier package, use the specified preparation and packaging together.

The surroundings matter as well. For routine storage of a stable mixed collection at normal indoor temperatures, aim for 40–50% relative humidity, unless the firearm requires different conditions. [6]

Check the conditions before starting a long storage period. Use a temperature-and-humidity monitor with saved readings near the firearms, away from direct heat from a heating rod. Our humidity-target and monitoring guide covers setup and firearm-specific conditions.

If humidity remains high, correct that before leaving the firearm unattended. A damp room may need room-level dehumidification so less moisture enters the safe. Desiccant inside an enclosure takes up water vapor, but it eventually needs drying or replacement according to its instructions. Check its service indicator while preparing the firearm for storage. [7]

Make inspection part of the plan

Browning recommends periodic inspections for rust. [4] For a newly prepared storage arrangement, we recommend an initial check after one week, followed by monthly inspections while the firearm remains unused. Check sooner after a water leak or a sustained rise in humidity.

At each inspection, look for new rust, particularly where the gun touches its support. Check the contact material for dampness and compare the humidity history with the earlier record. Photograph any suspect spot so you can see whether it changes.

Handle prepared metal as little as practical during the check. If inspection requires opening a preservation package, renew any disturbed protective coating before resealing it according to the storage procedure.

Prepare it again before firing

Remove any storage insert and packaging before returning the firearm to service. Inspect the bore and chamber, then carry out the manufacturer’s preparation for use. SIG’s P365 manual specifically requires removing lubricant from the bore and chamber before firing. [1]

Reapply operating lubrication where the firearm’s instructions call for it. If inspection reveals corrosion in the bore or chamber, have a qualified gunsmith assess the firearm before firing.

A storage accessory you can maintain

XeroMag is designed to take the place of a compatible firearm’s magazine during unloaded storage. It contains activated alumina desiccant for passive moisture management, alongside a separate Cortec VpCI-170 corrosion-inhibitor element. It can stay in place between inspections, working without electricity or batteries.

The removable baseplate gives access to both consumables for replacement, so you can renew the materials and keep using the insert. The separate Desco humidity indicator card provides a visual check during inspections. Choose the listed XeroMag configuration for your pistol or AR-15-pattern firearm, and remove it before loading or returning the firearm to service.

Sources

1. SIG Sauer P365 operator’s manual, revision 05, section 10.1 and preparation for use.

2. GLOCK: Caring for Your GLOCK, cleaning after use and adverse exposure.

3. Canadian Conservation Institute: Caring for metal objects, handling residues.

4. Browning: How should I store my firearm?, preservation and periodic inspection.

5. Ruger AR-556 instruction manual, printed pages 37–38.

6. Canadian Conservation Institute: Storage of Metals, CCI Notes 9/2, stable mixed collections.

7. Canadian Conservation Institute: Preparing silica gel for contained storage of metal objects, monitoring and servicing desiccant.