Had the barrel hood on a pistol, not a SIG, exhibit black flecks. They were pin head sized flecks. I assumed it was oxidation. I've seen occasions where there is a black stain that will not come off.

The rest of the gun with a stainless frame was fine. So, I'm wondering what exactly is going on if it is not oxidation and why, if it is oxidation, it is happening with stainless steel.

Upon cleaning lightly with a mildly abrasive pad, they came off, but there is what seemed to be some barely perceptible pitting. So, again, I assume it's oxidation.

There was some similar black flecks behind the trigger guard. That might be from perspiration or something on my hands.

It may be the barrel hood is not actually stainless steal, but it also didn't rust like carbon steal.

That sort of spotting/pitting is all too common with stainless cookware, where continued use with exposure to salts or other compounds common in foods and cooking will work into the metal. Like you found with your barrel, dark spots usually black in color are the result. Pitting usually has occurred in these areas. We have several stainless pots and saucepans that suffer from this; inevitable given their many years of use and service.

That barrel and gun of yours may have been exposed to salt-tinged air, perspiration or some chlorinated chemical at some point...who knows for certain. Keep in mind that stainless steel in general is only good at delaying and slowing down the effects of oxidation and rust, not preventing it entirely.

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Keep in mind that stainless steel in general is only good at delaying and slowing down the effects of oxidation and rust, not preventing it entirely.

Very true...a quick wipe down with any good gun oil is still in order even with stainless steel. Rod

Thanks for the information and corroboration. I expect it was perspiration. Interestingly, the barrel itself was fine.

I've heard for different ways to clean and remove the dark spots, one being a cleaner with oxialic like Bar Keepers Friend in a paste or liquid.

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Originally posted by Rodfac:

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Keep in mind that stainless steel in general is only good at delaying and slowing down the effects of oxidation and rust, not preventing it entirely.

Very true...a quick wipe down with any good gun oil is still in order even with stainless steel. Rod

What would you say is a good gun oil? Thanks in advance.

I have in the past just used REM oil in a spray can. However, Lucas make a good gun oil and they make their CLP in a liquid which I have now taken to putting on a cloth and using to wipe down my guns.

The odd thing about the one I mentioned is that is is stored in the same place and in the same way as all my others and none of the others exhibit the same issue.

However, I suppose it if came in contact with something in particular, it was not a storage issue.

Polish the gun with nevrdull found at any hardware store. Never dull will not change the finish texture and will clean the stainless and leave a nice protective wax on it. The black specs are either corrosion, or a dissimilar metal on/in the alloy. Such as steel dust or another metal that got onto the stainless and corroded.

Gentle polish with Flitz should remove black flecks.
REM oil is too light. I am a believer in Ezzox--as a protective coating.

http://www.6mmbr.com/corrosiontest.html

000 steel wool and oil will get the stains out.

Bob

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Originally posted by jimmy123x:
Polish the gun with nevrdull found at any hardware store. Never dull will not change the finish texture and will clean the stainless and leave a nice protective wax on it. The black specs are either corrosion, or a dissimilar metal on/in the alloy. Such as steel dust or another metal that got onto the stainless and corroded.

NeverDull is the BOMB on stainless guns, and it will take off the powder rings on the face of the cylinder for revolvers very well.

DO NOT USE IT ON BLUE GUNS. It will remove blueing.

Good advice on removal the black flecks. FWIW, some stainless pistols have carbon steel barrels "in the white" that owners might naturally assume are stainless. That was the case with several of my stainless Kimbers, and I believe Les Baer still uses carbon steel barrels, with only the barrel bushing being stainless steel, in his stainless guns.

I got a good deal on a P220 Carry Stainless Elite because it had those black fleck AND minor pitting around/under the grips.

It can happen to any stainless steel.

In my case, it was believed to be perspiration, but the gun was also kept in a safe in a port city.