A question about pitting in a barrel

[Skookum]

I noticed in the last few months that my 6mm BR was no longer living up to the accuracy it once held that was on par with the reputation of the cartridge. Barrel is a Hart chambered by Bob Carlock. It is a varmint rifle and it has about 1200 rounds down the tube which I know isn't much for this round, which is why I have one. I couldn't remember when the last time I cleaned it so I went ahead and ran some Bore Tech Carbon remover and it cleaned up pretty quick minus a small amount of copper. I ran a bore scope down the tube and found what appears to be pitting resembling a bug that ate through wood in numerous locations ranging from about 16-22" down the 26" long barrel. Anyone idea what could have caused this?

 

[Fuj]

4140 barrel ??

 

[DShortt]

It appears to me that at some point during it's life, it developed corrosion in the bore and what the images show is the damage from that.
I made the mistake of taking a rifle out of an air conditioned environment into high humidity several times one summer. I was appalled the next time I bore scoped it. Lesson learned.

 

[varget204]

pit/barrel worms, believe is flaws in the actual steel, have seen it in a couple of Brand New barrels

 

[hpshooter]

Can't say for sure but I did run into to this type corrosion in a chrome moly barrel that I knew had been stored in a vinyl case in a high humidity environment.

 

[pintopete]

I have seen the same thing in some used rifles that I own. Since I purchased them used, I don’t know what caused the corrosion. It’s amazing how it does look like a worm pattern. Hart barrels are usually stainless, at least in recent years.

 

[Skookum]

4140 barrel ??

It's stainless

 

[pintopete]

One is factory steel, the other is a premium stainless.

 

[L.Sherm]

Top one is bore reamer marks that never got pre- lapped out before the button was pulled.
I have seen inclusions on a cut barrel after it had about 200 rounds down it that weren't there brand new and on a stick of CM barrels after they were heat treated but they looked different than these.
If its a button barrel could be the acid etching they used right before the lube and button was pulled or solvent that was used in cleaning didn't get taken all out.

 

[Tommie]

Have you used moly coated bullets?

 

[pintopete]

Top one is bore reamer marks that never got pre- lapped out before the button was pulled.
I have seen inclusions on a cut barrel after it had about 200 rounds down it that weren't there brand new and on a stick of CM barrels after they were heat treated but they looked different than these.
If its a button barrel could be the acid etching they used right before the lube and button was pulled or solvent that was used in cleaning didn't get taken all out.

Interesting! I believe the top one is a hammer forged. It’s a factory Remington barrel. The bottom was sold to me as a Hart. It is stainless.

I have not used moly bullets, but bought it used.

 

[L.Sherm]

Here's a pic of the inclusions I was talking about.

 

[varget204]

Can't say for sure but I did run into to this type corrosion in a chrome moly barrel that I knew had been stored in a vinyl case in a high humidity environment.

All the barrels I have seen with them have been stainless barrels

 

[mharp]

These pics are causing me PTSD. Lost about a dozen barrels with that exact look. All BR barrels. Some set aside for big matches. Corrosion.

 

[Lone Hunter]

Have one in a 6x45 barrel that has about 80 rounds on it. Haven’t got to do much load work up yet. Stainless Match.

 

[dusterdave173]

Think maybe from water based bore cleaners
I stored one with new barrel for a while--went back and there were two or three places like that--they were black when discovered--scrubbed clean and both look like your photos--I think it was Boretech water based cleaner left in the bore???? Mine shoot and group really well so no effect except in my mind Just my thoughts on the matter who knows?

 

[joshb]

Maybe old habits or I just like the smell. After using my various cleaners that contain ammonia, I give the barrel a thorough cleaning using Hoppes and a coat of oil.
I just want to make sure I get all that water based crap out of my barrel.

 

[JEFFPPC]

Maybe old habits or I just like the smell. After using my various cleaners that contain ammonia, I give the barrel a thorough cleaning using Hoppes and a coat of oil.
I just want to make sure I get all that water based crap out of my barrel.

Smart habits Josh. I do the same. I always end with Hoppes then a preservative oil.

 

[KMart]

There is also an metal eating bacteria that is out there. There are several articles on the internet. The stuff eats carbon steel as well as stainless. Scientists have put a name to it and how it works.
Do a google search for Metal eating bacteria.

 

[DShortt]

There is also an metal eating bacteria that is out there. There are several articles on the internet. The stuff eats carbon steel as well as stainless. Scientists have put a name to it and how it works.
Do a google search for Metal eating bacteria.

I personally wouldn't put too much stock in that particular cause. Simply because there are a LOT of barrel images I've seen that look like the OPs. I've seen it a handful of times myself and I haven't looked down nearly as many barrels as some folks.
I'm convinced it's the result of corrosion. If I learn something new I might change my mind, but I've not encountered anything yet.