Why Can Stainless Steel Rust?

We use high-quality stainless steel in our products, but there are times when rust spots or "red spots," as they are commonly called, appear on it. How and why does this happen? Stainless steel is an alloyed (i.e., impure) steel that is resistant to corrosion in various environments. This resistance is achieved by incorporating at least 12% chromium into the alloy. Chromium reacts with oxygen, resulting in the formation of a chromium oxide film on the metal surface. It is this oxide film that protects the steel from the harmful effects of corrosion.

In the production of weapons, martensitic and austenitic steels are most commonly used. Martensitic steels are stronger and more resistant to impact, but they have lower corrosion resistance. On the other hand, austenitic steels are softer but more resistant to corrosion.
The steels used in weapons are exposed to aggressive environments and high levels of stress, which can significantly impact their durability. When shooting, aggressive sulfur and chlorine compounds are formed, which corrode the protective oxide film on the surface of the steel.

Mechanical damage, moisture, gunpowder residue, and dirt are all ideal conditions for corrosion.

When cleaning, rubbing the bullet inside the barrel, or handling it carelessly, the oxide film is damaged, exposing the metal and causing rust. Sandblasting the parts also reduces the corrosion resistance of the steel. Many micro-scratches left after the abrasive treatment, violate the integrity of the oxide film, as a result of which the sandblasted part will begin to rust faster than a similar polished part. But military realities dictate their own conditions, and no one will work with a shiny and glaring barrel on the front, the rifle needs to be painted. And it is here that we come to the problem of painting stainless steel. Paint simply does not stick to polished steel due to the oxide film, which makes the painting process pointless. Sandblasting helps to prepare the surface of the part for painting, and the paint adheres securely to the surface after sandblasting. Therefore, each solution has its own advantages and disadvantages. The specific use of weapons makes it impossible to maintain the steel perfectly, which increases the risk of rust on the parts.

As with everything else, you have to sacrifice one thing for another when choosing steel. In our case, we prioritize the characteristics of steel that will allow us to provide the greatest hardness, strength, and reliability, which is critical for high-precision shooting. This results in a reliable and durable rifle with multiple layers of protection in every component, but it requires proper maintenance to avoid corrosion issues.