Is This Carbon?

[AICS308]

This picture is from a new barrel with 300 rounds fired. Just completed cleaning without abrasives and saw this with a borescope. I am not sure if it is carbon or something else. Any suggestions on what this is and if it needs to be removed.

 

[TheCZKid]

Looks like you're starting to get slight fire cracking, just past where the brass neck ends. And below that is where the carbon ring normally forms. So that ring is good to remove if it gets thick, as it can cause issues if it gets too pronounced.

 

[RegionRat]

Your bbl will tell your chronograph when it is time to "scrub to bare metal", or if your regular cleaning is still working. Your 300 rounds is doing pretty good, so you must be doing something right.

TLDR: I would let that bbl run unless there is a lot of copper downstream or the DOPE is drifting too fast.

Most kinds of shooting (it is very difficult to generalize) don't require a bare metal cleaning and your regular regimen with solvents should keep you in the game with stable DOPE.

There are places where the round counts and shooting demand different cleaning regimens, such as BR and match shooting, but tactical and hunting contexts can be very different.

When that dark zone color turns thick enough, or when you get a build-up like where TheCZKid explained, your velocity and pressure will change faster than "normal" and you will struggle to keep your DOPE under control. That means it is time to scrub to bare metal.

Since the proliferation of chronographs and access to things like Kestrels and weather data, it isn't difficult to keep a DOPE book and know if the gun isn't tracking due to fouling.

If we scrub to bare metal every time we go home from the range, we can kill the life of a barrel in short order. The definition of "regular cleaning" versus "scrub to bare metal" is easy to demonstrate, but hard to put into just a few words.

You can always spin a fresh bronze brush near the throat if all you are seeing is near there, without going nuclear on the whole bbl. Just don't go crazy with abrasive pastes or you can remove more than just the fouling.

Allowing yourself to learn how many rounds it takes to tip-over, and when the time comes that "regular" cleaning isn't enough, is an important lesson. A shooter needs to learn how their shooting in their context calls for regular cleaning or going nuclear. Good Luck. YMMV

 

[AICS308]

I do most of my shooting at 600 yards and some at 1000. This barrel has been great so far with 200 - 12x and 200 - 9x although both were shot in perfect conditions. I’m trying to not do anything that might damage the barrel since this is the best shooting one I’ve had. The dope is spot on at 600 so far.

Thanks for the input,

 

[RegionRat]

Just a coincidence that a friend has recently posted a video of a bad case of carbon fouling.
I'll attach a YT video that Gary Eliseo posted so you can see a real bad example.

 

[William Vogel]

This picture is from a new barrel with 300 rounds fired. Just completed cleaning without abrasives and saw this with a borescope. I am not sure if it is carbon or something else. Any suggestions on what this is and if it needs to be removed.


View attachment 1698471

Without a few more pictures a little farther down the barrel it’s hard to assess. It appears to be a light carbon build that is staining the low spots but your cleaning process has removed everything that could impede the bullet entering or traveling through the throat. I have a very difficult time getting this area of the barrel to shine as bright as a few inches further down the barrel and I stop cleaning as you have. The discoloration may be just a heat affected zone. I use a borescope to monitor my cleaning process and once I began to view the inside of the barrel, I had to improve my cleaning process considerably.

 

[Sandstorm]

Some discoloration is normal, but Gary's Video look's like its never even had a patch down or any cleaning whatsoever.... Wow.

 

[6.5 forever]

Some discoloration is normal, but Gary's Video likes like its never even had a patch down or any cleaning whatsoever.... Wow.

You have that right for sure. I've never seen a barrel that bad

 

[DShortt]

Referring to the video :
People talk bad about borescopes. A situation like this is where they are tremendously helpful. I doubt that ANY product is going to get that much carbon fouling out without multiple applications and effort. But. The borescope allows you to monitor the condition so it's obvious if progress is being made or not.
A clean patch only tells you nothing is being removed. There's no telling what is or is not left behind without looking.

 

[AlNyhus]

This picture is from a new barrel with 300 rounds fired. Just completed cleaning without abrasives and saw this with a borescope. I am not sure if it is carbon or something else. Any suggestions on what this is and if it needs to be removed.


View attachment 1698471

A bit of discoloration and a bit of carbon, is all. The transition is pretty rough.

 

[AICS308]

The neck freebore transition is what I was worried about. It looks like fire cracking but after 300 rounds I’m little surprised to see that. Then thought maybe it was a carbon buildup. I’m shooting at 2635 fps with Berger 200.20X, which I didn’t think was over loaded.

Should I address this or wait to see if it continues to grow?

 

[jelenko]

A clean patch only tells you nothing is being removed.

Amen!

 

[RegionRat]

The neck freebore transition is what I was worried about. It looks like fire cracking but after 300 rounds I’m little surprised to see that. Then thought maybe it was a carbon buildup. I’m shooting at 2635 fps with Berger 200.20X, which I didn’t think was over loaded.

Should I address this or wait to see if it continues to grow?

It isn't abnormal to see this pattern forming as it always starts at the facet from the neck to the freebore diameter and spreads downstream with cycles. When we run heavier bullets, we see it sooner.