Preventing Rust on Your Surplus Firearms

The good thing about surplus firearms is that you can often find really rare or excellent guns in great condition at an unbelievable price.

The (potentially) bad thing about surplus firearms is that sometimes they’ve seen quite a bit of service, and hard service at that.

Add to this the fact that sometimes surplus firearms are very old, and you have a recipe for a gun that’s at risk of rust and decay. 

The focus of this article will be on the former considerations. Here’s what you need to know about keeping your surplus guns in pristine shape - specifically as it relates to rust.

Why Rust Is a Killer of Surplus Guns (and All Firearms)

First and foremost, rust (and to a lesser degree, other forms of oxidative corrosion, such as those that will impact aluminum parts) will decrease the value of your firearm.

More importantly, rust can cause moving parts to seize, which can cripple the action and operation of the gun. Worst of all, rust in the bore can damage accuracy.  

That’s just the shortlist of problems, but it paints a compelling picture. With that said, here are some of the main ways you can prevent rust from gaining a foothold on your precious surplus firearms’ steel components.

Keep the Gun Clean and Dry

Most importantly, you need to make sure the gun is clean and dry after use. If you buy the gun in question as a collectible and never fire it or have it outside, this should be easy enough.  

However, if the surplus firearm in question has actually been restored and used for any sporting purposes in the field, it is important to strip it and clean it when you get home.

After cleaning, you must make sure to fully dry all constituent parts before reassembling the firearm. Rust can’t happen if conditions don’t favor it, and moisture is one of the most noxious of all corrosion catalysts.

Don’t Shoot Corrosive Ammo

If the surplus gun in question is chambered in a round for which ammo loaded with corrosive primers or propellants were made in the past, be conscientious of this, especially if you ever actually shoot the gun.

Back in the day, some ammo was loaded with corrosive primers such as potassium chlorate or sodium perchlorate. Avoid these rounds if possible, and if you do shoot them, make sure to thoroughly clean your gun immediately after you visit the range.

Also, before the modern era, cartridges were loaded with black powder, not modern smokeless propellants. Regardless of what’s used for a primer, the fouling produced by black powder is thick, heavy, and extremely hygroscopic.

Shooting black powder cartridges can be enjoyable for lots of reasons, not the least of which is the historical authenticity. However, if you ever do, make sure you thoroughly clean the gun and leave no fouling in the bore, action, or in contact with any of the other steel components.

This fouling will cause rust. Make sure to remove it if you ever expose your gun to it.

Oil (or Wax) Metal Parts

For guns that see use, a gun oil like Hoppe’s Gun Oil or Rem Oil is perfect not just to lubricate moving parts, but also to put down a protective, insulative barrier on the surface of steel components to seal it off to corrosion.  

A thin layer of oil should also be applied to all fasteners, the barrel, and all other steel parts in order to prevent rust.

However, all oils will evaporate if left long enough, so it’s not always the best idea to only use oil on a gun in the safe.

In the case of collectibles, or guns that are bought and stored or displayed but never fired, microcrystalline wax is actually a better option.

Microcrystalline wax, unlike oil, will not evaporate, which makes it a better long term solution. It is also more stable and like oil will prevent oxidation.

The best thing about microcrystalline wax is that if applied properly, it can then be buffed to improve the finish and aesthetic of the treated steel component.

Store Wisely

In addition to keeping the gun clean, eschewing corrosive ammo, and keeping the steel components protected by oil or wax, it is also important to store the gun in a safe place, with respect to temperature and relative humidity.

Temperature is more of a concern with wooden components, as swings in temperature can cause wood to warp or crack, but with respect to humidity, that’s the real thing you need to keep your eye on here.

High humidity is a precursor to rust, as chronically humid conditions will cause steel to rust more quickly.

As we’ve covered in previous posts, the ideal humidity range for most surplus firearms is between 30% and 50%, and on the lower end is better. Steel does fine at levels below 30%, the problem lies with the rest of the wood furniture.

Also, it is critical not just to keep the humidity low, but to make sure there aren’t big humidity swings. Consistency is just as important as dry conditions.  

One more note - there are special dehumidifiers you can specifically buy that are expressly designed for gun safes. Get one of these, install it in your gun safe, and it will help protect your investment in your priceless historical and surplus firearms.

Explore Surplus Firearms Here

In the event that you landed here because you’re looking into the prospect of expanding your current gun library, you’re in the right place. In addition to carrying an encyclopedic and exhaustive range of gun parts and accessories, including parts for rare and historic firearms, we also carry a significant number of surplus guns.  

Explore our collection of surplus firearms and get in touch with us if you’re looking for a model, or even a gun part, that you don’t see listed. We would be more than happy to help you find what you’re looking for.

And at that point, make sure you follow some of the tips contained in here to make sure you prevent rust on your guns.