A question about pitting in a barrel

[jackieschmidt]

416 stainless will corrode. A friend gave me several old Unlimited barrels that I stood next to a water cooler in one of our shop buildings. The stood right there for several years.

one day I walked by and noticed how awfull they were looking. I took one home, cleaned the bore, and took a look. It was horrible.

 

[Rick H.]

Odd looking barrel with the black bulb thing on it. Muzzle brake or tuner?

Rick H.

 

[Downhill]

I have seen a lot of corrosion like this on natural gas pipelines. In the Barnet Shale formation there is a naturally occurring microbe in the condensate from natural gas wells. It anchors itself to the interior wall of a pipeline and has caused leaks in as little as 5 years. Seems to be more frequent in the higher grades of pipe(harder steel), the old soft steel lines resist this for decades ( repaired a pipeline put in the ground in 1939 and the corrosion was minimal).

 

[M-61]

First I’m not a metallurgist. 400 series stainless is magnetic. That tells you there is ferrous material involved. You have that and you’ll wind up with corrosion. 300 series is not magnetic but not as tough. ( doesn’t screw with the compass on a boat if people even use them anymore) But there are endless variations of stainless as there is carbon steels. Plus all of the hundreds of Hardening techniques. I’ve often wondered why carbon steel barrels are rarely seen in bench rest rifles. They certainly are tougher.
Then all of the things done to aluminum. Spars on an aircraft’s wings. That’s strong especially when you consider the flex and load.
Wish riflewoman was still on this site.

 

[jxb]

Odd looking barrel with the black bulb thing on it. Muzzle brake or tuner?

Rick H.

Um that's an old school pooperplug shooter

 

[S Miller]

Good interview with Erik Cortina and Frank Green. Interview #64, 56:34sec in on YouTube. I’ve done this and have those same marks.

 

[FNSafari]

Stain-less, not stain-proof it seems.

 

[DShortt]

No matter what the cause, I'd have to believe a good coating of oil would have prevented it.

 

[358WCF]

I've noticed similar spots in several rifles. Only 1 or 2 leave traces of copper downstream from these spots & need a bit more care. The rest are cleaned normally. Wondering if a Tubb final finish bullet or 2 wont clean off the marks? Not really that concerned, but may try it in the worst offenders.

 

[JMayo]

1200 rounds in a 6bra is getting close to being used up, imo 1700 Max.
Remember, a bore scope makes things look worse than they are.