The Infamous Carbon Ring

[Richard Coody]

I know the pics aren't great but you can see what is going on.

My question is does the carbon ring form at the end of.the chamber where the throat starts or at the end of the throat where the lands start?

And what is the best way to clean this area?

 

[Bart B.]

It can start anywhere in front of the case mouth depending on cartridge. What cartridge are you using?

Clean it out with a good bore cleaner and a bronze bore brush.

To me, freebore starts at the chamber mouth and is a constant diameter forward to where the rifling starts at the back of the throat (or leade) starts. The throat angles down to bore diameter. Some cartridge chambers have no freebore and their throat starts at the chamber mouth. 30-06 and 300 Win Mag, for example, per SAAMI chamber specs.

 

[KMart]

I have found that the quickest way to get rid of it is to use the felt cleaning plugs, available through Brownells, and Isso paste. The plugs are caliber specific and apply a lot of pressure in a small area. J-B and other things like it will also work. These are abrasives and will work on the throat metal as well, so don't be real aggressive. Short stroke it 8-10 times in the area, clean it out and check it with your bore scope until you get a feel what is going on.
You can try and stay ahead of the ring, once it is gone, by paying special attention to the throat area with a good carbon cleaner and a bronze brush during your normal cleaning. Hoppe's ain't what it use to be. I use a mixture of SeaFoam carburetor cleaner and marvel mystery oil.
The carbon ring is very hard. Kind of like the stuff formed on the cylinder head and pistons of an engine.

 

[Richard Coody]

It can start anywhere in front of the case mouth depending on cartridge. What cartridge are you using?

Clean it out with a good bore cleaner and a bronze bore brush.

To me, freebore starts at the chamber mouth and is a constant diameter forward to where the rifling starts at the back of the throat (or leade) starts. The throat angles down to bore diameter. Some cartridge chambers have no freebore and their throat starts at the chamber mouth. 30-06 and 300 Win Mag, for example, per SAAMI chamber specs.

6BR

do you remove the bore guide and shortstroke that area with a carbon cleaner. I really don't want to damage.the barrel. This rifle is shooting good.

 

[Richard Coody]

I have found that the quickest way to get rid of it is to use the felt cleaning plugs, available through Brownells, and Isso paste. The plugs are caliber specific and apply a lot of pressure in a small area. J-B and other things like it will also work. These are abrasives and will work on the throat metal as well, so don't be real aggressive. Short stroke it 8-10 times in the area, clean it out and check it with your bore scope until you get a feel what is going on.
You can try and stay ahead of the ring, once it is gone, by paying special attention to the throat area with a good carbon cleaner and a bronze brush during your normal cleaning. Hoppe's ain't what it use to be. I use a mixture of SeaFoam carburetor cleaner and marvel mystery oil.
The carbon ring is very hard. Kind of like the stuff formed on the cylinder head and pistons of an engine.

I have a PMA tools chamber cleaning kit that came with foam plugs. I use sea foam in my outboard periodically. Great stuff but never thought of it for a carbon cleaner in my rifle.

 

[Bart B.]

I've short stroked throats and freebores with a patched jag smeared with JB paste or a yellow paste made with Hoppe's No. 9 and dental pumice. It was sold as "Martin's Mustard." That pumice is one of the finest non-embedding abrasives known. Dental hygenist's clean hardened crud off our teeth with it.

Short stroking bronze brushes in bores ain't a good thing. It may not harm the bore but always ruins the brush. Bronze is softer than steel.

 

[watercam]

I've short stroked throats and freebores with a patched jag smeared with JB paste or a yellow paste made with Hoppe's No. 9 and dental pumice. It was sold as "Martin's Mustard." That pumice is one of the finest non-embedding abrasives known. Dental hygenist's clean hardened crud off our teeth with it.

Short stroking bronze brushes in bores ain't a good thing. It may not harm the bore but always ruins the brush. Bronze is softer than steel.

If you use a slightly undersized brush with a patch wrapped around it is possible to switch directions without ruining the brush AND still clean into the corners of yours lands and grooves.

 

[hogpatrol]

Do a search on carbon ring. You'll get twenty different methods for removal, all of them are the best.

 

[Bart B.]

If you use a slightly undersized brush with a patch wrapped around it.....

My favorite jag for 30 caliber patches is a 22 caliber bronze brush; especially the military ones with thicker, stiffer bristles as military 30 caliber ones are.

 

[Richard Coody]

If you use a slightly undersized brush with a patch wrapped around it is possible to switch directions without ruining the brush AND still clean into the corners of yours lands and grooves.

Actually that is how i do all the patches in my barrel. Never tried backing one up though.

Just got back from the range. Cleaned my bore with my usual boretech eliminator. Then i took my chamber cleaning kit an ran a patch wrapped brush soaked.in ballistol into the throat. Going.to let it soak a while and see what happens.

If this carbon is anything like the hard carbon on the tail of an AR bolt you have to scrape it off.

 

[Joe R]

I know the pics aren't great but you can see what is going on.

My question is does the carbon ring form at the end of.the chamber where the throat starts or at the end of the throat where the lands start?

And what is the best way to clean this area?

Richard,
I use Iosso every 300-400 rounds. I use one of these jags, wrap a patch around it and give it 40 strokes.

http://forum.accurateshooter.com/threads/parker-hale-cleaning-jag.3926456/
http://forum.accurateshooter.com/threads/parker-hale-cleaning-jag.3926456/
Good luck,

Joe

 

[drags]

I've short stroked throats and freebores with a patched jag smeared with JB paste or a yellow paste made with Hoppe's No. 9 and dental pumice. It was sold as "Martin's Mustard." That pumice is one of the finest non-embedding abrasives known. Dental hygenist's clean hardened crud off our teeth with it.

Short stroking bronze brushes in bores ain't a good thing. It may not harm the bore but always ruins the brush. Bronze is softer than steel.

Hi Bart can the Martin's Mustard be purchased anywhere, if not do you know the formula for making it?
Drags

 

[gme]

witches brew, cost way too much but will strip all the carbon away

 

[lawrence97]

What you have pictured does not look bad at all. That looks like the free space between the end of your neck and the chamber. The shorter you trim your brass the more room you leave for stuff to develop at the end of it.

A true carbon ring will be thicker, affect the Guns performance, boost pressure and at the extreme end, it will scratch a bullet if you load a cartridge and then remove it without firing. It will also affect your cartridge base to bullet ogive readings if setting/measuring your seating depth.

It's best to stay ahead of it by spinning a bronze brush or tight patch in that area to prevent build up followed with an abrasive (jb or iosso) every 200 rounds.

 

[snakepit]

I have found that the quickest way to get rid of it is to use the felt cleaning plugs, available through Brownells, and Isso paste. The plugs are caliber specific and apply a lot of pressure in a small area. J-B and other things like it will also work. .

Thanks for the information, I just ordered some and the adapter from Brownells or should I say backordered.

 

[seymour fish]

What you have pictured does not look bad at all. That looks like the free space between the end of your neck and the chamber. The shorter you trim your brass the more room you leave for stuff to develop at the end of it.

A true carbon ring will be thicker, affect the Guns performance, boost pressure and at the extreme end, it will scratch a bullet if you load a cartridge and then remove it without firing. It will also affect your cartridge base to bullet ogive readings if setting/measuring your seating depth.

It's best to stay ahead of it by spinning a bronze brush or tight patch in that area to prevent build up followed with an abrasive (jb or iosso) every 200 rounds.

Lawrence, "the shorter you trim brass", Exactly !

 

[rogn]

????? https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias=aps&field-keywords=dental+pumice&tag=accuratescom-20 ------ https://www.amazon.com/dp/B003AYPRLA/?tag=accuratescom-20

 

[msinc]

What you have pictured does not look bad at all. That looks like the free space between the end of your neck and the chamber. The shorter you trim your brass the more room you leave for stuff to develop at the end of it.

A true carbon ring will be thicker, affect the Guns performance, boost pressure and at the extreme end, it will scratch a bullet if you load a cartridge and then remove it without firing. It will also affect your cartridge base to bullet ogive readings if setting/measuring your seating depth.

It's best to stay ahead of it by spinning a bronze brush or tight patch in that area to prevent build up followed with an abrasive (jb or iosso) every 200 rounds.

I have only had the carbon ring a few times. It was always in a small caliber high velocity type cartridge and I shot more rounds in a row than I typically do. The only way I have ever been able to remove it WITHOUT unnecessary wear or damage was to use some kind of carbon dissolving cleaner, like carburetor spray, and a larger than bore size bronze brush {example; a 6mm in a 224 bore rifle, 30 cal in a 7mm, etc.} spun by a drill. I attach the brush to a section of cleaning rod that will get it to the throat and spray the cleaner into the chamber. Then, spin it slow and barely advance until I feel it hitting the neck/throat area.
You want minimal time spinning this way and so I let it go for maybe 10 seconds and patch and scope the bore. This is one of those things where the old "prevention" vs. "cure" comes into play....don't let it get so bad that you have to dwell in that throat area too long to clean it.

Lawrence, "the shorter you trim brass", Exactly !

Exactly +2!!!! In fact, rifles that display a tendency to build the carbon ring should be "fitted" to brass case length looking thru a scope to make sure the mouth is "right there".....I mean, it's not as if most of us don't trim to an exact point every load anyways. And so what, if you just do it for this one rifle....if it cures the ring or at least delays it.

 

[lpreddick]

A borescope tells it all. Burnt propellant residue (carbon) is deposited in the bore after the first round fired as well as in the gap between case mouth and bore...the carbon ring. If this deposit is ignored for several hundred rounds it becomes extremely hard and patching doesn't touch it. A bronze brush that barely makes contact in this area(the chamber neck) if spun slowly with your favorite cleaner will eventually scrape it out. There is usually a slightly dark stain left in the steel and is of no consequence. Hoppes makes a very stiff nylon brush as does iosso that when spun with jb every few shots removes this deposit quickly...borescope confirmed.

 

[dkhunt14]

There are actually two different carbon build-ups. You can get it at the end of the case mouth in the actual chamber. It also build up in the leade and throat also. Both can be detrimental to accuracy. Either can also build pressure. I use a worn out bronze brush with a patch wrapped around. I apply a little Iosso to the patch and short stroke the throat about 20 to 30 times and short stroke once throught the rest of the barrel. The carbon in the chamber can be cleaned out by twisting a bronze brush with carbon cleaner like C4. The brush should fit snug. Matt