Is “Stainless Steel” Really Rust-Proof?
Some folks feel that they don’t have to worry about rust and corrosion on stainless steel barrels, actions, and other components. That’s not really true. “Stainless” is a bit of a misnomer. First, there are different types of stainless steel alloys, with different degrees of rust resistance. 300 series stainless is more corrosion resistant than the 416 stainless commonly used in barrels. The composition (by percentage weight) of 416 stainless is 0.15% carbon, 12-14% chromium and the rest iron. 416 stainless steel lacks the roughly 10% nickel content that makes the 300 series more corrosion resistant in atmospheric conditions. But because 416 handles pressure better and is easier to machine (than 300 series steel), 416 stainless remains the better choice for barrels.
Though some grades of stainless are more corrosion-resistent, ALL varieties of stainless steel can rust if they are not handled and stored properly. Forum reader Kells81 observed: “Wanna see some rusted stainless? Go to the big “C” brand store in Ft. Worth. Every stainless gun they have on the used gun rack is rusted.” Tom Easly of TRE Custom explains: “Sweat is very corrosive. Sweat and blood will rust many stainless steels. I hate to handle my guns or drip on them when I sweat. It really helps to just wipe them good with a wet rag, dry and wipe on a light coating of gun oil. I think most stainless barrels are made from type 416 stainless, and it is generally pretty corrosion resistant, but not when exposed to sweat, blood, or chlorates (corrosive priming), and some other electrolytes.”
Forum member Jacob, who is studying materials science at LSU, provides this technical information: “The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface. This coating is a ‘passive’ film which resists further ‘oxidation’ or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids that contain oxygen. Once the layer has formed, we say that the metal has become ‘passivated’ and the oxidation or ‘rusting’ rate will slow down to less than 0.002″ per year (0.05 mm per year).
Unlike aluminum or silver, this passive film is invisible in stainless steel. It’s created when oxygen combines with the chrome in the stainless to form chrome oxide which is more commonly called ‘ceramic’. This protective oxide or ceramic coating is common to most corrosion resistant materials.
Halogen salts, especially chlorides, easily penetrate this passive film and will allow corrosive attack to occur. The halogens are easy to recognize because they end in the letters ‘ine’. Listed in order of their activity they are: fluorine, chlorine, bromine, iodine, astatine.
These are the same chemicals that will penetrate Teflon and cause trouble with Teflon coated or encapsulated o-rings and/ or similar coated materials. Chlorides are one of the most common elements in nature and if that isn’t bad enough, they’re also soluble, active ions. These provide the basis for electrolytes. The presence of electrolytic solutions can accelerate corrosion or chemical attack.”
CONCLUSION: Stainless steel barrels and components won’t rust nearly as fast as blued steel, but you still have to take precautions — particularly removing sweat and corrosive salts from the barrel. Also, don’t let moisture build up inside or outside of the barrel. We recommend wiping your barrels and actions with Eezox, or Corrosion-X after each use. These are both extremely effective rust-fighters that go on thin, without leaving a greasy residue. (Eezox leaves a clear finish, while Corrosion-X has a slightly waxy finish.) Also store your guns in Bore-Store bags when the guns go in the safe. Bore-Stores wick away moisture, and the synthetic fleece inner surface is treated with rust-fighting chemicals. Bore-Stores also protect your guns against dings and scratches.
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Tags: 416, 416 Stainless, Bore Store, Corrosion, Eezox, Rust Proofing, Salt, Stainless
Eezox is one of the best products I have in my range bag its also an excellent lubricant, AR-15 for example
It’s funny that Kells81 mentioned the rusty stainless guns at the “C” store in Fort Worth. We have the same collection of “orange rifles” at our store here in Buda, TX as well.
I got sweat on my 420R SS aftermarket barrel, wiped it off without considering that rusting was a possibility, low and behold, a few days later…RUST!
Please don’t even consider having barrels made from 303, 304 or 316 stainless steel. While more corrosion resistant than 416, these steels do not have the strength to withstand the high pressures associated with expanding gasses produced by firing of cartridges. They also tend to gall, and are very difficult to machine, due to work hardeneing. DON’T DO IT!
Keep in mind that even the best steel is still 80% + iron
Stainless steel most definitely can rust. Fortunately it is easy to remove the rust and re-passivate the surface of the steel to avoid recurring corrosion. We sell an excellent non-hazardous citric acid based product for this purpose. Visit http://www.citrisurf.com or call 847-854-2800 to learn more about CitriSurf 77 Plus and CitriSurf 2310 for rust removal and passivation of stainless steel.
Bead blasting stainless steel with media that has been used on regular steel is a common problem leading to rust specs on the stainless. The small bits of regular steel left behind in the media are embedded in the stainless and those small bits rust.
Buy a tin of RENAISSANCE wax and use it. Resists finger prints and sweat, and protects your barrel, action, and stock better than anything else available!
Like the old saying, “stainless is not stain free”.
It is lots easier to take care of though.
The Navy, which uses a lot of 300 series and some 416, put it into perspective decades ago. They never call it stainless steel, they call it CRES, which stands for Corrosion Resistant Steel, a much more accurate description. Of course, outside of the Navy and some other elements of the DoD, when I refer CRES I get a blank stare, lol.
Just coat everything with Renaissance Wax, stainless or not. I handle in the white carbon steel without ever wiping afterwards and have yet to see even the slightest trace of rust. It’s like a dry oil film that never runs off.
With all the components like sweat, water, sea air and heat from the weather and when being fired, of course the rust-proof effect will decrease. What could be the best products in order to make a gun’s stainless factor lasts longer?
“Bore-Stores wick away moisture”
The definition of wick (to absorb or draw off by capillary action) leads me to ask, does the firearm need to be in contact with the Bore-Store to achieve this? This seems a more accurate description of wicking, and implies direct contact to achieve it.
Say (a) a stainless gun is placed in a Bore-Store, (b) there’s moisture on the surface of the firearm, and (c) the wet part of the gun is NOT in contact with the Bore-Store, although it is enclosed by the entire bag.
Or is the Bore-Store helping pull moisture by another means, say evaporation and absorption from the air in the bag?
I make my living in the marine industry. I constantly have to tell my customers this:
It is stain-less, not stainless!
If you want true stainless, use titanium.