Carbon ring questions....

[KenOath]

IMO the best investment you can make right now is either a bore scope, or an endoscope with a 1 to 2 centimeter focal distance. The endoscope will allow you to see the whole chamber, neck and leade to identify trouble areas and confirm your cleaning process, whereas the bore scope gives a more "soda straw" view, a very close look at a small area.

Both have their uses and strong points however, I prefer the broader view so I use the endoscope which I also use to look in the muzzle end and plainly see copper build up where it is more likely to occur.

With that in mind, to clean out carbon rings I put a bronze brush on a section of 3 piece cleaning rod, chuck it in a cordless drill and spin the brush in the neck/lead, then confirm with the camera.

There are many inexpensive endoscope cameras available, some that will bluetooth to your phone or PC (I just bought this one https://www.amazon.com/dp/B01MYTHWK4/?tag=accuratescom-20 ), but not many with a focal distance close enough, so choose wisely. NOTE: the one I just bought has a 5 cm minimum focal distance, which is too far for good viewing in a chamber.

I've been using a Snap-On BK5500 like this one https://www.ebay.com/p/Snap-on-BK5500-Visual-Inspection-Scope-Camera-Device/1011864405 for many years with good success.

That scope you just bought a looks good but has an 8.5mm camera head, I may be able to see the lands in my 7mil but that’s about it..

 

[Texas10]

What cleaning agent do you prefer when twisting that brush around in that area? Do you move some back and forth also or just purely twist? Can I twist with the drill too fast?

Don

You can use just about any carbon removal liquid, or none, the brush does the work. I spin and move back and forth, and check with the camera to confirm I'm working the problem area. Drill speed is fast or slow, doesn't seem to matter. IMOP, you can't hurt barrel steel with a bronze brush, although some will disagree.

 

[Texas10]

That scope you just bought a looks good but has an 8.5mm camera head, I may be able to see the lands in my 7mil but that’s about it..

Yes, but the chamber, throat and lands are plainly visible, and it'll look down the muzzle too. I do have another one (5 mm) that will fit down my 223 barrel, is water proof and has a 15 ft cable, not that it makes it any more useful. Again, not really a replacement for a bore scope.

One trick I do use is to put a cleaning rod down the muzzle and use it to reflect the endoscope light against the barrel walls. A lot of additional detail can be revealed this way.

 

[BenPerfected]

If you are looking for exceptional accuracy, the bore scope is an important $1000+tool. If you buy one, you aren’t likely going to sell it until you exit CF competition.
Ben

 

[KenOath]

Yes, but the chamber, throat and lands are plainly visible, and it'll look down the muzzle too. I do have another one (5 mm) that will fit down my 223 barrel, is water proof and has a 15 ft cable, not that it makes it any more useful. Again, not really a replacement for a bore scope.

One trick I do use is to put a cleaning rod down the muzzle and use it to reflect the endoscope light against the barrel walls. A lot of additional detail can be revealed this way.

If you are looking for exceptional accuracy, the bore scope is an important $1000+tool. If you buy one, you aren’t likely going to sell it until you exit CF competition.
Ben

I have the Lyman but am looking at some other options, the endoscope will give ma another different view will have a look for the 5mm version Texas10.. I still haven’t been able to get a look through a Hawkeye to compare..

 

[Dusty Stevens]

I have the Lyman but am looking at some other options, the endoscope will give ma another different view will have a look for the 5mm version Texas10.. I still haven’t been able to get a look through a Hawkeye to compare..

Dont do it unless youre ready to buy. Over all these years of people trying to find a cheaper alternative there hasnt been an acceptable one yet. The lyman is borderline hobbyist type quality but it does take somewhat revealing pics to post on the net. Hard to do that on a hawkeye cheap. An inspection scope is so far away from actually seeing tool marks or carbon hiding in the groove corners once you see thru a hawkeye youll sell something to get one if you have to.

 

[Jdne5b]

Dont do it unless youre ready to buy. Over all these years of people trying to find a cheaper alternative there hasnt been an acceptable one yet. The lyman is borderline hobbyist type quality but it does take somewhat revealing pics to post on the net. Hard to do that on a hawkeye cheap. An inspection scope is so far away from actually seeing tool marks or carbon hiding in the groove corners once you see thru a hawkeye youll sell something to get one if you have to.

+1

I bit the bullet for a Hawkeye over the Labor Day sales. The lyman I had isnt even in the same ball park.

 

[mike a]

I found a couple pics about carbon ring in front of case mouth with a 28Nosler:
Before:
View attachment 1065555
After cleaning:
View attachment 1065557
On thing to notice here is that his trim length put case mouths a relative mile from chamber end.
This is a big contributor to the buildup, along with high neck clearance, and slow pressure peak.
If you're getting much for carbon sooting down your necks, you're building a carbon ring in chamber front.

Excellent pics, so the carbon is accually in the chamber (neck) not on the leade. I see copper there. If the case length had been closer do you think the ring would be forward of the neck?

 

[Hengehold]

Excellent pics, so the carbon is accually in the chamber (neck) not on the leade. I see copper there. If the case length had been closer do you think the ring would be forward of the neck?

I believe that the idea is that the carbon ring appears between the end of the case mouth and the end of the chamber mouth where the lead begins. In theory, if your cases were all fired at the max possible length, then there would be no place for the carbon ring to form in front of the lead. The threat of a carbon ring formation is present if cases are fired in a chamber and the necks are shorter than the chamber. For example, if you always trim the OAL of your brass to the minimum trim-to length before every loading then there is a lot of space for a carbon ring to form. That is my understanding anyway.

As an aside, I shot my AR service rifle (223) in EIC and NRA highpower competitions without much cleaning. Never experienced pressure issues due to carbon ring. Longest stretch I went between barrel cleanings was 1,000rds and it was still hammering at 600 yds. With my palma rifle I used to clean it about every 400-500 rds and never experienced pressure issues from a carbon ring. I am curious if some cartridges or powders are more prone to them than others.

-T

 

[mikecr]

If the case length had been closer do you think the ring would be forward of the neck?

Hengehold described it well.
- Trimming tight to chamber end leaves high angles for blowback to maneuver around, and buys your necks time to seal, which stops all blowback. The gas has very little distance to travel, and cannot put momentum to heavy carbon within it.
- Trimming loose to chamber end provides more distance and lower angles for blowback to get a run backwards. This, with enough gas flow to give heavier carbon momentum to reach between neck/chamber all the way back between shoulder/chamber. When the neck snaps to sealed, the carbon traveling doesn't stop immediately, but bunches up to form a ring at the sealing area(case mouth locations).
In the picture provided earlier, notice the ring doesn't form at chamber end, but further back where it bunches up like a snow drift.

The further you trim away from chamber end, the greater the aggression of this buildup.
Where cases mouths are within 5thou of chamber end, and neck clearance is rational, you'll see <1/16" length of carbon soot on necks, and likely burn out the barrel before a carbon ring forms to problem.

Another issue with sloppy chamber end clearances is in it's potential affect to SD. Blowback affects to pressure peak. Where you see case sooting to shoulders, you're probably seeing higher SD. Ideally, necks snap to solid seal immediately, but gas working it's way back there is countering neck sealing. It's pushing on shoulders to move the case. It's affecting attributes of containment timing.
There is nothing good in it.

Often I see it advised to 'trim em all to the shortest case'. The context of it being for consistency.
I feel like this is bad advice. There is no evidence that consistent trim lengths override the detriments of excess chamber end clearance. Even with an underbore (like 6PPC, 30br, etc.) where such a clearance does not hurt, because these necks will always seal as quick as it gets, there is also not an advantage to consistent trim lengths. And hunting capacity cartridges, burning more slower powders at way lower pressures would be affected more by excess clearance than by inconsistent trim lengths.
I say form to tight clearance(COW forming), or let the necks creep ever toward a goal clearance, and then manage that (it's easy).
I'm suggesting you're better to mitigate formation of carbon rings, rather than fighting to remove them.

 

[Delfuego]

Often I see it advised to 'trim em all to the shortest case'. The context of it being for consistency.
I feel like this is bad advice. There is no evidence that consistent trim lengths override the detriments of excess chamber end clearance.

Clark and Trudy Fay told us they shoot it once and trim 4/1000 under trim length and forget about it. Never have to trim them again.

 

[mikecr]

'Trim length' is undefined. Chamber end is locally determined. You set YOUR local trim length from there.

 

[Delfuego]

4/1000 under SAAMI trim length

Shoot more, trim less, have more fun...

 

[JMayo]

So what I am gleaning from the post so far is I need a small rod that i can twist and attach a brass brush (one size larger) coated in IOSSO cleaner/polisher. I can do this after my normal barrel cleaning with the bore guide still installed. Insert the short rod with coated brass brush up around the throat/start of land area and twist round and round and short strokes in and out. Doesn't matter about brush changing direction during these short strokes. I need to do this after every cleaning? Or should i do this with something like Boretech C4?

I'm sure i got something wrong here. Please help me tune this method. Thanks for you alls help.

You don't have a chamber cleaning tool ? The kit comes with an end to clean behind lugs. Buy big mops put a patch on it to clean chamber of cleaning chemicals
And no bore guide you're cleaning where it seals.https://deweyrods.com/product/bac-bolt-action-lug-recess-cleaning-kit/
(I am no expert ...! )

 

[mikecr]

4/1000 under SAAMI trim length

This does not define a clearance.
And your appeal to authority contributes nothing to reasoning.
So if you think I'm wrong, then by all means bring your understanding to bear.

 

[Capt. Oblivious]

So what I am gleaning from the post so far is I need a small rod that i can twist and attach a brass brush (one size larger) coated in IOSSO cleaner/polisher. I can do this after my normal barrel cleaning with the bore guide still installed. Insert the short rod with coated brass brush up around the throat/start of land area and twist round and round and short strokes in and out. Doesn't matter about brush changing direction during these short strokes. I need to do this after every cleaning? Or should i do this with something like Boretech C4?

I'm sure i got something wrong here. Please help me tune this method. Thanks for you alls help.

I stick that short rod in a hand dril and let it sp

Hengehold described it well.
- Trimming tight to chamber end leaves high angles for blowback to maneuver around, and buys your necks time to seal, which stops all blowback. The gas has very little distance to travel, and cannot put momentum to heavy carbon within it.
- Trimming loose to chamber end provides more distance and lower angles for blowback to get a run backwards. This, with enough gas flow to give heavier carbon momentum to reach between neck/chamber all the way back between shoulder/chamber. When the neck snaps to sealed, the carbon traveling doesn't stop immediately, but bunches up to form a ring at the sealing area(case mouth locations).
In the picture provided earlier, notice the ring doesn't form at chamber end, but further back where it bunches up like a snow drift.

The further you trim away from chamber end, the greater the aggression of this buildup.
Where cases mouths are within 5thou of chamber end, and neck clearance is rational, you'll see <1/16" length of carbon soot on necks, and likely burn out the barrel before a carbon ring forms to problem.

Another issue with sloppy chamber end clearances is in it's potential affect to SD. Blowback affects to pressure peak. Where you see case sooting to shoulders, you're probably seeing higher SD. Ideally, necks snap to solid seal immediately, but gas working it's way back there is countering neck sealing. It's pushing on shoulders to move the case. It's affecting attributes of containment timing.
There is nothing good in it.

Often I see it advised to 'trim em all to the shortest case'. The context of it being for consistency.
I feel like this is bad advice. There is no evidence that consistent trim lengths override the detriments of excess chamber end clearance. Even with an underbore (like 6PPC, 30br, etc.) where such a clearance does not hurt, because these necks will always seal as quick as it gets, there is also not an advantage to consistent trim lengths. And hunting capacity cartridges, burning more slower powders at way lower pressures would be affected more by excess clearance than by inconsistent trim lengths.
I say form to tight clearance(COW forming), or let the necks creep ever toward a goal clearance, and then manage that (it's easy).
I'm suggesting you're better to mitigate formation of carbon rings, rather than fighting to remove them.

Very good info here

 

[Martin52]

I posted this info somewhere else on this site -

Use a chamber length gage then trim to say 0.005 under. Sinclair make/sell one. A useful tool.

 

[Dusty Stevens]

I posted this info somewhere else on this site -

Use a chamber length gage then trim to say 0.005 under. Sinclair make/sell one. A useful tool.

Note that this only works if you do not have a carbon ring already

 

[Delfuego]

This does not define a clearance.
And your appeal to authority contributes nothing to reasoning.
So if you think I'm wrong, then by all means bring your understanding to bear.

You want to start a fight look elsewhere. Do you want to help the OP or do you just want to be right? My point on all my posts, if you were reading, was that the alleged carbon ring in front of the brass is not what you should focus on or worry about. The hard carbon in the barrel is the biggest concern.

Delfuego out

 

[mikecr]

Ok, your point is what I was fishing for. Thank you.