What is this borescope pic?

[randello88]

The rifle is a Bergara b14 hunter, I used it hunting for many years, it took rain, fog, snow amd blizzards. After an hunt in rough weather i always cleaned the bore but I have to admit i never babied it. Since I go hunting at least 30 times per year and i take one animal more or less everytime, sometimes hunting 3 times a week during autumn and winter, of course it was impossible to clean the bore to bare metal everytime i shot. I preferred to keep accuracy and POI consistent keeping the barrel fouled. I stored it always in a humidity controlled room. There is absolutely no surface rust, even where the finish of the rifle went totally off for rubbing against the backpack or against my body. It has shot more or less 500 .308 win factory rounds and it is still very accurate, shooting easily 0.3 MOA with a couple factory loads.

After all these years i decided to clean the bore to bare metal since this rifle is going to retire for a while and it will be used only occasionally from now on.

I found this spot with what looks like pitting/corrosion more or less 15 inches from the chamber (it is a 22 inch barrel). There are a few other spots looking like this but smaller than this one in the same area of the bore. The rifling looks good in the rest of the bore and it wasn't difficult at all to clean all the fouling and copper.

I am not worried about this because the rifle shoots very well and this spots are not located in the most critical portion of the bore but i am curious about what could have caused this. It is a button rifled barrel and it was the first time i borescoped it.

Thanks for the input guys!

 

[Capt Call]

That looks corrosion that was under copper. I had a barrel that looked like that on 1 of my truck guns that didn't get cleaned regularly.

 

[Capt Call]

 

[Thump_rrr]

The real question is does it still shoot as accurately as is did before?
If it doesn’t get wet or condensation I don’t clean till the groups open up around 150 rounds or so.
If it gets wet I’ll push a couple of wet patches followed by some dry patches then a patch of oil.
I will then run a dry patch before the next time I shoot.

 

[randello88]

That looks corrosion that was under copper. I had a barrel that looked like that on 1 of my truck guns that didn't get cleaned regularly.

How can copper cause this pitting if the rifle is stored in a humidity controlled enviroment?

 

[randello88]

The real question is does it still shoot as accurately as is did before?
If it doesn’t get wet or condensation I don’t clean till the groups open up around 150 rounds or so.
If it gets wet I’ll push a couple of wet patches followed by some dry patches then a patch of oil.
I will then run a dry patch before the next time I shoot.

It shoots amazingly well and served me well for years, never a single issue, always went bang, killed many deer. I couldn't be happier with it. Last week i tried shooting some groups just to check function before putting it away for a while: 3 5 shot groups, 2 at 100 m, 2 at 200: the worst one was measuring 0.39 MOA

 

[randello88]

View attachment 8638375

Expand please, what is the context?

 

[Oryx]

How can copper cause this pitting if the rifle is stored in a humidity controlled enviroment?

Metals don't only react to humidity ....

 

[Capt Call]

Expand please, what is the context?

To me that looks like the same thing happened to your barrel. I may be wrong but, I think it is moisture getting under the copper and setting. Even if the rifle is kept in controlled environment it is not controlled when you are out hunting. If the rifle still shoots well don't over think the bad spot.

 

[randello88]

Metals don't only react to humidity ....

I know, i am asking how copper can cause pitting on steel, i didn't knew it was a thing

 

[randello88]

To me that looks like the same thing happened to your barrel. I may be wrong but, I think it is moisture getting under the copper and setting. Even if the rifle is kept in controlled environment it is not controlled when you are out hunting. If the rifle still shoots well don't over think the bad spot.

True, no need to overthink it but, if there was a way to prevent that in the future, it would be nice to know it.
How to prevent that if you hunt in bad weather, considering that, if you hunt often, cleaning to bare metal the bore everytime will probably make more damage/first shot accuracy issues than not doing it?