is it firecracking or a carbon ring

[hoz53]

there is a ring around the barrel rite in front of the end of free bore. it sure looks like fire cracked to me but i know this is the same area carbon rings form. ive scrubbed it with no change to. its a ruger 77 factory barrel in 7R
not all that many rounds on it either. what is that ring?

 

[rwj]

IMHO it’s firecracking…

 

[Webster]

View attachment 1584527there is a ring around the barrel rite in front of the end of free bore. it sure looks like fire cracked to me but i know this is the same area carbon rings form. ive scrubbed it with no change to. its a ruger 77 factory barrel in 7R
not all that many rounds on it either. what is that ring?

View attachment 1584527there is a ring around the barrel rite in front of the end of free bore. it sure looks like fire cracked to me but i know this is the same area carbon rings form. ive scrubbed it with no change to. its a ruger 77 factory barrel in 7R
not all that many rounds on it either. what is that ring?

Scanning electron microscope image at 25X mag. Fire cracking shouldn't have a sharp beginning and end edges. It should continue down the barrel for some distance. My image: carbon build up on the left before fire cracking (hot gas erosion). Don't understand the appearance of the textured area in your pix.

 

[jelenko]

I'd go with it probably being carbon and use some Iosso type cleaner. As mentioned, my fire cracking extends much further down the bore.
If it's carbon, you'll see changes in the area after a few sets with patches/brushes/patches on brushes that you're using with the abrasive cleaner.

PS. What causes the white lines in the pic?

 

[Murray Brook]

I would think that the black ring is the beginning of a carbon ring with some fire cracking just in front. JMO

 

[Shooter13]

That's firecracking looking like you have the beginning of carbon ring or you've cleaned it out

 

[Bill Norris]

That's firecracking looking like you have the beginning of carbon ring or you've cleaned it out

That's what it appears to be.

 

[AlNyhus]

Barrels can also be discolored in the area where carbon builds up.

 

[JMayo]

Goodness, if there is such a thing of negative # fb You've got it.
That cracking is a normal after 500 rounds imo

 

[EEP]

This may not help as it looks similar but different. This was in a 6Dasher with about 800 rounds on it. This is before and after pics of fire cracking and after JB paste with brush on drill.
BEFORE


AFTER JB

 

[DShortt]

Agree with the above. It's not one or the other. It's both.

Remove the carbon and it'll look much better.

 

[rwj]

Last I knew carbon was black and non-reflective…

 

[DShortt]

A borescope is a learning experience. The angle of the light makes the way things look change significantly.
All I can do it interpret the images shown. Actually being able to manipulate the bore scope would make a lot of difference in my level of confidence.
The poster above still has a carbon ring, but it's significantly smaller and likely not a problem for several shots.
The OP has a lot of carbon in there that should be removed. Then the potential firecracking issue can be evaluated.

 

[boltman13]

Due to the lack of dark color i am somewhat leaning toward fire cracking, however, it looks circumferal to me which is characteristic of a carbon ring. It could be a little of both I suppose. Attacking it with a good carbon ring effort and reborescoping it shouldn't harm the barrel further. Is this a Remington 7mm Magnum? If so a quick firing of multiple rounds with no time for the barrel to cool could result in fire cracking on the lands and your picture could be of the land running away from the throat down the bore. Good luck.

 

[hoz53]

IMHO it’s firecracking…

after a bunch of scrubbing I figured that out- Thanks

 

[hoz53]

View attachment 1584551
Scanning electron microscope image at 25X mag. Fire cracking shouldn't have a sharp beginning and end edges. It should continue down the barrel for some distance. My image: carbon build up on the left before fire cracking (hot gas erosion). Don't understand the appearance of the textured area in your pix.

yes after closer examination it does continue farther down the bore and ive cleaned enough to feel its firecracking. i dont know about the textuted area thanks

 

[hoz53]

I'd go with it probably being carbon and use some Iosso type cleaner. As mentioned, my fire cracking extends much further down the bore.
If it's carbon, you'll see changes in the area after a few sets with patches/brushes/patches on brushes that you're using with the abrasive cleaner.

PS. What causes the white lines in the pic?

yes i cleaned with iosso before this post and alot yesterday including with a battery drill as i dont have much to lose with this barrel. not much change and moving the borescope around i could see it extended further up the bore so i guess its fire cracking thanks

 

[hoz53]

I would think that the black ring is the beginning of a carbon ring with some fire cracking just in front. JMO

i think thats true but after alot of scrubbing the black ring is still there. thanks

 

[hoz53]

Due to the lack of dark color i am somewhat leaning toward fire cracking, however, it looks circumferal to me which is characteristic of a carbon ring. It could be a little of both I suppose. Attacking it with a good carbon ring effort and reborescoping it shouldn't harm the barrel further. Is this a Remington 7mm Magnum? If so a quick firing of multiple rounds with no time for the barrel to cool could result in fire cracking on the lands and your picture could be of the land running away from the throat down the bore. Good luck.

well i cleaned it quite alot and didnt get it alot different. i guess i got some carbon out because i could see the firecracking extending up the bore. i think it is/was both now. it is a remington 7mm magnum and very skinny. i only shoot it 2 or 3 shots and let it cool but prob shot it faster in the past. my pic does have the groove running to the right down the bore and the firecracking perpendicular to that is going around the circumferance if that makes sense-- thanks

 

[hoz53]

A borescope is a learning experience. The angle of the light makes the way things look change significantly.
All I can do it interpret the images shown. Actually being able to manipulate the bore scope would make a lot of difference in my level of confidence.
The poster above still has a carbon ring, but it's significantly smaller and likely not a problem for several shots.
The OP has a lot of carbon in there that should be removed. Then the potential firecracking issue can be evaluated.

yes i think i removed the carbon and can see the firecracking running further down the bore. thanks