Another 'is this a carbon ring'?

[Tesoro]

This is inside my 6br 22in bbl plinker. I just cleaned the heck out of barrel with jb paste and even put in a 30 cal nylon brush into the neck/leade area to power scrub it with a drill. I have the lands and grooves pretty much carbon and copper free but this pesky nice and even ring remains. I am starting to think it is carbon laying below 'ground level' in a machining groove and dosent hurt anything. I put a fired case in chamber for reference and you can see it on the bottom. Is this a faux carbon ring or should I keep scrubbin?! The rifle was shoooting well before cleaning. it put 5 in a row in 6in at 1000. Thx

 

[rwj]

IMHO… I wouldn’t clean anymore.

On another aspect of the picture, is the case fully inserted? The gap between case mouth and shoulder appears larger than expected.

 

[Pres100]

Agree with RWJ .... not seeing the carbon ring, but pretty short case length

 

[jpx2rk]

You can soak it with BT C4 for a bit using a bore mop and patch, then use a new or oversize bronze brush and position the brush where it's just into the lands, and twist it, and short stroke it.. Check with borescope and repeat as needed. You need to get the brush in just the right spot and then spin it while moving the brush just a little bit to get the spiral bristles to get all of the ring out.

 

[Tesoro]

I re-inserted a fired case never trimmed with bolt in and took another pic..I guess I pushed the other one back with the borescope head. End of case at 2 and a land at 8. The darker part of ring looks so even that I assume it is just carbon in the bottom of a tool mark. A spot where new carbon will stick to but cleaning that anymore is fruitless as the black is probably 'below grade' ?

 

[Coyotefurharvester]

No, not a carbon ring.

 

[Rick300]

It's easy to have a shadow there that makes you think it's a carbon ring. Chased a few of those over the years. Kinda like a stump deer or a bush elk.

 

[dmoran]

@Tesoro
1st picture below is with a piece of brass in the chamber (like yours above), showing the end of the case mouth, the end of the chamber, and beginning of the free-bore, before cleaning/removing the carbon build up/ring:

This next picture below is after some cleaning of the area, again with the case in place:

This 3rd picture is the same, but with the case removed:

At this point the chamber-end is clean & carbon free, with a square transition up to the free-bore, no longer a rounded transition formed from carbon layer (aka: carbon ring).
The area in the picture is like say 85% cleaned & carbon free. What is left to be cleaned in the picture is the remaining heavily carbon layered beginning of the free-bore, where the cracking of the carbon layer itself still remains, that can be easily seen in the photo (and of course the rest of the free-bore/throat and bore not in the picture).

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[Tesoro]

Ok thanks for this! So in pic 3 are you saying that the even black ring is ok, now that you cleaned the buildup/ramp up on the freebore side of that ring? Are you good to shoot at this point as no pic #4 supplied with no black band at all?

 

[gqhoon]

Ok thanks for this! So in pic 3 are you saying that the even black ring is ok, now that you cleaned the buildup/ramp up on the freebore side of that ring? Are you good to shoot at this point as no pic #4 supplied with no black band at all?

The black ring you’re referring to is shadow cast by the light in the Borescope camera. It’s not a carbon ring.

 

[AlNyhus]

If your bore scope is long enough, try looking at that are from the other direction.

 

[jelenko]

The area in the picture is like say 85% cleaned & carbon free.

Still. It looks really clean to me

 

[Tesoro]

If your bore scope is long enough, try looking at that are from the other direction.

I am definitely gonna look from the breech side now! Thanks everyone.I might have to change my handle to 'shadow chaser'. !