Stubborn Carbon Ring Removal

[Cardboard Assassin]

I got a borescope recently and had a look inside my tired old 6.5CM RPR barrel.

I'm pretty diligent about cleaning but not ridiculously so. The rifle gets cleaned before its stored for any length of time and I would estimate it never goes more than 100 rounds between cleaning.

At this point the barrel (stock) is probably getting close to end of life with ~2500 rounds through it and I have noticed the accuracy drop off. With 40.6 grains of H4350 it would send 140 Hornady BTHPs around 2650 and would make a cloverleaf at 200 but I cant get the same consistency any more.

With this in mind I figured I would check for the carbon ring and it seems to have one. The first picture is the "As Found" condition where the rifle was cleaned and put away and inspected recently when I acquired a borescope.

The second & third "As Left" pics are after cleaning (3 sessions) with Boretech carbon cleaner. I left a patch soaked in cleaner jammed into the throat area for an hour and then brushed with a slightly oversized nylon brush.

I think its *slightly* better but certainly not clean. With a standard rifle running a well used CHF barrel is it unrealistic to expect to get rid of it all?

My thought process is get rid of the carbon ring (as best I can) then shoot it to see if I still have issues (the gun was never picky until the last couple of hundred rounds), if so then the barrel is toast and I'll replace it.

These suckers sure are hard to move.

 

[Mauser06]

I'm not convinced that ring matters. I haven't found a way to get rid of it either. Every barrel I see has it right where the case ends. Maybe I'm wrong.

What will kill a barrel is a throat that's fouled up bad. I can actually feel mine with a patch when it's bad. My rod won't spin with the rifling for the first 4-6" or so either.

Only cure I've found is Iosso or your favorite abrasive cleaner. It won't take much. I can have mine cleaned out in a couple minutes and a couple patches.


When mine stops shooting and I clean the throat out, it goes right back to hammering. That ring you show never changes.




If you are that far into the barrel, I'd experiment on it. Clean it till it can't get any cleaner. I'd bet it shoots again. But, Once the throat is all fire cracked, it doesn't take long for fouling to get bad and accuracy to fall off.

 

[Cardboard Assassin]

I'm not convinced that ring matters. I haven't found a way to get rid of it either. Every barrel I see has it right where the case ends. Maybe I'm wrong.

What will kill a barrel is a throat that's fouled up bad. I can actually feel mine with a patch when it's bad. My rod won't spin with the rifling for the first 4-6" or so either.

Only cure I've found is Iosso or your favorite abrasive cleaner. It won't take much. I can have mine cleaned out in a couple minutes and a couple patches.


When mine stops shooting and I clean the throat out, it goes right back to hammering. That ring you show never changes.




If you are that far into the barrel, I'd experiment on it. Clean it till it can't get any cleaner. I'd bet it shoots again. But, Once the throat is all fire cracked, it doesn't take long for fouling to get bad and accuracy to fall off.

I'm thinking the same, nothing to lose, this barrel doesn't owe me anything and I plan to replace it but I like playing around and hopefully learning something. If I can eek out a few more rounds with good accuracy thats a bonus.

The beauty of it is even if I do get too carried away and damage it its no real loss.

I do wonder if the fact it is a mass produced barrel CHF barrel has a bearing, I`m guessing these don't get hand lapped etc so will never be as smooth as one of the higher end barrels and as such will never clean as well.

 

[Cascade Hemi]

Soak it in C4 and then scrub it with Ioso. It'll come out easily.

 

[Reload10]

Use an abrasive, a brush, and spin it with a drill. You won't hurt a thing.

 

[Cardboard Assassin]

Is is Iosso Bore Cleaner? Please see attached picture.

I may struggle to get my hands on this stuff, dont know if it is readily available where I am (Canada).

Are there any alternatives?

 

[Huskydriver]

Clr.....

 

[Reload10]

Yeah that's it. BR guys used toothpaste before branded barrel abrasive was made, go ahead and brush it with toothpaste if you're in a pinch

 

[Krob95]

CLR works wonders forsure. I’ve used it many time to clean carbon rings in my old 6BR

 

[Cardboard Assassin]

CLR works wonders forsure. I’ve used it many time to clean carbon rings in my old 6BR

I have some CLR and I have thought about it.

I have read a ton of info regarding this (a lot from this forum with input from respected folks like Frank Green etc) and the views are wide ranging, one thing that is holding me back is the fact it is not a stainless barrel.

Having said that if I applied CLR via a patch plug, left it there for minimal time (15 minutes) and then cleaned the barrel and chamber thoroughly with Boretech Eliminator or similar in theory that would remove / neutralize the CLR and hopefully get rid of the carbon ring without damaging anything.

 

[spife7980]

I have some CLR and I have thought about it.

I have read a ton of info regarding this (a lot from this forum with input from respected folks like Frank Green etc) and the views are wide ranging, one thing that is holding me back is the fact it is not a stainless barrel.

Having said that if I applied CLR via a patch plug, left it there for minimal time (15 minutes) and then cleaned the barrel and chamber thoroughly with Boretech Eliminator or similar in theory that would remove / neutralize the CLR and hopefully get rid of the carbon ring without damaging anything.

That’s fine. The etching that was discovered was when it was left soaking overnight. A bit on a patch for a few minutes will be fine.

 

[Krob95]

I left it sit for 30 minutes. Then scrubbed the chamber with a nylon brush attached to a drill and then patched out with MC-7 and then dry patches. No issues.

 

[918v]

Is is Iosso Bore Cleaner? Please see attached picture.

I may struggle to get my hands on this stuff, dont know if it is readily available where I am (Canada).

Are there any alternatives?

A bronze brush

 

[Mauser06]

Iosso, JB, flitz etc etc. Lots of abrasives. I've come to like iosso.


I've tested CLR. I was at wits end. I plugged the barrel for 24hrs. It did NOT touch hard carbon. Nor did boretech or anything else I soaked and swabbed with.

Got iosso. 2 patches later I was blown away by my bore scope.


Hard baked carbon and powder/loose carbon fouling are 2 different animals.

Use your favorite carbon cleaner on patches after 100rds till they come out clean. Get your bore scope out and take a look.


What manufacturers claim and what some guys post about just don't match what I've actually witnessed. Your mileage may vary. Maybe I do it wrong. I've learned what works for me.

Solvents and bronze brushes for normal cleaning and maintenance. Iosso periodically to deep clean back to steel.

 

[Cascade Hemi]

A bronze brush

Nylon brush with a patch wrapped around it coated in Ioso. Three patches total, gently sweeping back and forth.

CLR is lame, and just like a lot of other fads will be gone before long too.

 

[918v]

Nylon brushes are for bitch boys.

 

[XTREM HTR16]

Will JB bore brite paste work as well as Iosso?

Asking for a friend.

 

[Cardboard Assassin]

Will JB bore brite paste work as well as Iosso?

Asking for a friend.

What I'm getting here is that so long as it is a mild abrasive it should do the trick.

A thorough cleaning afterwards for the purposes of removing all of the abrasive paste sounds important too, I imagine leaving some in would result in the bullet removing a small amount of metal as each round passes down the barrel.

 

[Cardboard Assassin]

A bronze brush

Haven't tried that.

I`m assuming we are talking about a bronze brush with a solvent of some kind (Bore Tech carbon remover or similar)?

 

[918v]

Haven't tried that.

I`m assuming we are talking about a bronze brush with a solvent of some kind (Bore Tech carbon remover or similar)?

Yes, run a couple wet patches, let it soak, then run a bronze brush in one direction down the bore 7 times, then a wet patch and repeat several times.

 

[Cascade Hemi]

Nylon brushes are for bitch boys.

Careful, you might cut yourself on that edge.

 

[Deleted member 10043]

I don't see anything out of the ordinary with that barrel's history.

 

[Deleted member 10043]

I'm thinking the same, nothing to lose, this barrel doesn't owe me anything and I plan to replace it but I like playing around and hopefully learning something. If I can eek out a few more rounds with good accuracy thats a bonus.

The beauty of it is even if I do get too carried away and damage it its no real loss.

I do wonder if the fact it is a mass produced barrel CHF barrel has a bearing, I`m guessing these don't get hand lapped etc so will never be as smooth as one of the higher end barrels and as such will never clean as well.

As you can see you've cleaned enough to determine it doesn't matter. You had no signs of pressure as a result of a ring. But you can see another issue that it is toasting. You did good getting 2500 out of it. After 1500 I would have ordered a new one in case it took a while.

 

[Deleted member 10043]

Nylon brushes are for bitch boys.

They are good for wrapping a patch around.

 

[Cardboard Assassin]

As you can see you've cleaned enough to determine it doesn't matter. You had no signs of pressure as a result of a ring. But you can see another issue that it is toasting. You did good getting 2500 out of it. After 1500 I would have ordered a new one in case it took a while.

I know 2500 is typical for 6.5CM and I suspect the barrel is trash but I aint too troubled if that is the case as I have other rifles and can wait for a new barrel.

What do you mean by toasting?

 

[Cardboard Assassin]

Yes, run a couple wet patches, let it soak, then run a bronze brush in one direction down the bore 7 times, then a wet patch and repeat several times.

Is a bronze brush more aggressive than a nylon brush? Can it damage the barrel?

 

[918v]

Is a bronze brush more aggressive than a nylon brush? Can it damage the barrel?

Yes it’s more aggressive. It actually removes carbon buildup instead of gliding over it like nylon. It won’t damage the barrel. I run it only one way to prevent wear to the crown. But it’s not going to wear the bore. Bronze brushes have been around for ever.

 

[Cardboard Assassin]

Yes it’s more aggressive. It actually removes carbon buildup instead of gliding over it like nylon. It won’t damage the barrel. I run it only one way to prevent wear to the crown. But it’s not going to wear the bore. Bronze brushes have been around for ever.

Thanks for the info.

I`m taking the rifle out to try tomorrow with it cleaned as per the pics (still some carbon there for sure) but I am going to grab a bronze brush from my LGS and try this out afterwards.

If I can find a procedure thats works it will serve me well for my other rifles (I just built a high end 6BR that is starting to develop a carbon ring), as mentioned previously I dont mind experimenting on this rifle as the barrel is at / getting close to end of life.

I have often wondered if dragging the brush back through the barrel was a good idea so I am going to try only going only one direction as you mention.

 

[brianf]

no abrasives...every barrel maker that posts on this site consistently says no abrasives in their barrels

chemicals and brushes are always recommended by them

additionally that recommendation is always after they say clean your barrel more often

 

[Cardboard Assassin]

One more question about brush size - as the carbon ring is located before the bore but instead where the brass ends (ie bigger than the bore) what size of brush should be used?

This is a 6.5 gun (264") - would a 270" brush be the correct size? Or bigger?

 

[spife7980]

One more question about brush size - as the carbon ring is located before the bore but instead where the brass ends (ie bigger than the bore) what size of brush should be used?

This is a 6.5 gun (264") - would a 270" brush be the correct size? Or bigger?

It ends ahead of the brass. Get a brush that matches your caliber and youll be fine. They come sized accordingly.

 

[Deleted member 10043]

In calibers what is your current bullet/case seating depth into the lands?

 

[Cardboard Assassin]

Picked up a bronze 6.5mm brush today, gonna shoot the rifle tomorrow to get a feel for what (if any) improvement there is from the cleaning to date and then have another go at removing the carbon ring.

 

[DownhillFromHere]

This subject has been addressed ad nauseam on SH and elsewhere. Glad the OP has read comments from Frank Green regarding abrasives and drills. And CLR.

Yes, CLR will etch a barrel - if it's left in the barrel too long. Used properly, it's very fast, completely effective, and causes no etching or other damage. It's only good for carbon. It won't remove copper.

I wet a bore mop or a patch on a subcaliber brush (.22 for 6.5CM), push it atop the carbon ring, leave it there for five minutes (never ever more than 15 minutes for really tough carbon), pull it out, follow with two dry patches, and finish with regular cleaning product like Hoppes or whatever.

It's important not to soak the mop or patch to the degree that CLR runs out of the bore and gets into or onto bit that it will hurt.

 

[30cal user]

Free All works and bronze bushes last one to two cleaning and then you need to pitch them

 

[Cardboard Assassin]

Free All works and bronze bushes last one to two cleaning and then you need to pitch them

Why is that? Do they wear away?

They're surprisingly cheap anyways.

 

[spife7980]

Why is that? Do they wear away?

They're surprisingly cheap anyways.

They bend a bit and arent as straight up firm. Ive never actually found it to be an issue. And honestly, I prefer them once they have worn in a bit. New brushes make me afraid my carbon cleaning rod is gonna break trying to get them started.

People say the nylon can have the carbon embedded in it and scratch the barrel etc. I think its all a bunch of hooey. The bullet dragging through at 60k psi is gonna do way worse than any brush will.

 

[918v]

Free All works and bronze bushes last one to two cleaning and then you need to pitch them

Bronze brushes last longer than one or two cleanings.

 

[Darkside-Six]

Nylon brushes won’t do much for carbon rings. You need a brass brush. Best way I’ve found in removing carbon rings is to push a patch soaked in CLR right there into the throat and let sit for about 10 minutes. Then scrub the hell out of it with a brass brush.

 

[JLP.Payette]

Boretech C4 and a Nylon brush works great for me. I just follow the instructions on the bottle.

 

[spife7980]

Boretech C4 and a Nylon brush works great for me. I just follow the instructions on the bottle.

Its always worked just fine for me too.

 

[B y r o n]

I've had good results using a product called Carb-Out from Sharp Shoot R Precision Products.

 

[Lesloan]

C4? Isn't plastic explosive a bit extreme?

 

[whatsupdoc]

I measure a fired case neck. then find a Bronze brush that is slightly larger than the case neck.
I shoot some Break Free CLP and a spin by hand, works great.

 

[81STFACP]

I use the reamer I designed and made by JGS with the same dimension as my finish reamer. The difference the carbon ring reamer/remover (CRR) just have the 45 degree cut in front of the neck and neck are sharpened. The body and shoulder are not. To use it, just run the reamer till it bottoms out, it won't change your headspace as the shoulder is not sharpened. The CRR is piloted you may have to pick a bushing to fit the bore.

If anyone is interested in having this type of reamer made, contact Sarah at JGS.

It works for me and for a few of friends who tried it.

I have another CRR made specific to the reamer we had JGS ground for the TX JRs High power shooting team. I support the kids spinning their barrels from blanks donated by Shilen. The coaches use their CRR as a maintenance tool. For the kids ARs I made a tight fitting guide both ID and OD. A rod extension with a u-joint connects it to the reamer.

 

[Marine52]

I use JB bore paste once or twice a year in addition to normal barrel cleaning with KG1 for carbon and KG12 for copper.

 

[Lug Nut]

I prefer chemical over abrasive.

I’ve found KG1 to be very effective for removing carbon.

 

[Terry of illinois]

bore.

 

[Terry of illinois]

Go to Alpha munitions web site . Look up the news section scroll down to article by Jim Kauber about carbon ring following his guide on cleaning out carbon ring . Works great take only a little more time and dose great job .

 

[Cardboard Assassin]

Go to Alpha munitions web site . Look up the news section scroll down to article by Jim Kauber about carbon ring following his guide on cleaning out carbon ring . Works great take only a little more time and dose great job .

Is this the one?

Carbon Ring Build-up, Resulting Problems and a Cure​

Though I’ve heard mention of carbon ring build-up it wasn’t until I got to the 6 Creedmoor portion of the large/small rifle primer comparison (last Kauber’s Corner article) was I aware first hand of the problems caused by carbon (powder residue) build up in the bore.
An established carbon ring manifests itself with sudden and progressive spikes in pressure; pressures bordering on the dangerous and in most cases degradation inaccuracy will result. The tremendous amount of heat and pressure transforms carbon fouling into a ceramic coating that is difficult to remove once it has welded itself in your rifling.
Every experienced match shooter, barrel builder, or gunsmith has his or her way of cleaning rifles but most will agree that a hard carbon ring can’t be removed by standard cleaning methods, it has to be scrubbed out. There lies the fine line between effectively removing the carbon ring and damaging your bore by using a compound too aggressive, overdoing the process, or a combination of both.
Not one to attempt to reinvent the wheel or waste time on the Internet trying to decipher the repeated BS from good, sage advice and recommendations, I’ll go directly to those I feel are true authorities based on years of personal experience and an application of said advice in the conduct of their livelihood. When I couldn’t figure out the pressure problems in my Benchmark Barrel built 6 Creedmoor I immediately drove the 20 minutes from home down to Arlington, WA to speak with my long time friends Ron Sinnema and Bill Broderick owner and manager respectively of Benchmark Barrels.
Below is their recommendation for removing the carbon ring:

Cleaning Carbon Ring In Rifle Barrels​

Carbon ring in the rifle bore can affect accuracy, pressure and velocity. It is more likely to occur in cartridges with large case capacity and small bore diameter. Carbon ring is best identified with a bore scope and will appear as dark and cracked areas of the bore. It is usually 1”-2” in front of the throat and chamber or within the first 30% of the bore. If you clean every 100-200 rounds in a suspect cartridge you may need to use the steps outlined below. It is ideal to inspect with a borescope to determine whether you have issues with carbon ring build-up and where it appears in the bore.

1. Clean all fouling and copper from the barrel using your normal cleaning method.
2. Use a coated rod with a quality jag that is undersize by one caliber – use high-quality flannel or cotton patches.
3. Fold a patch for a tight fit without sticking, cut/fold appropriately – it is important that your folded patch is tight in the bore almost to the point of becoming stuck.
4. Most carbon will be 1”-2” in front of the throat and chamber or within the first 30% of the bore.
5. Put a light coat of Simichrome on the patch being careful to place it on the sides of the patch and the front – this keeps the front of the patch from getting wet and the jag from pushing through the patch.
6. Push the wet patch all the way through the barrel in one even stroke.
7. Reapply Simichrome to the same patch as above and clean the first third of the barrel using short back and forth strokes – concentrate your effort on the first 30% of the bore – do this for about 2 minutes being fairly aggressive while keeping in mind that the barrel may warm up slightly, especially with the light contour barrels.
8. The patch will become loose in the bore during your 2-minute cycle, discard it, and create a new one as outlined in step 3. When you replace the patch during a cycle, do not apply more Simichrome, use the media left in the bore with the new dry patch.
9. Repeat steps 3 through 8 for ONLY two cycles*.
10. Clean as normal to remove the residual Simichrome and fouling. The objective is to remove the carbon ring but not to polish the bore to the point of being too shiny.

* If you do not have a borescope, do not exceed the recommended 2 cycle cleaning procedure with Simichrome. If you have a borescope, inspect so you know where to focus your effort and clean until most of the carbon is removed. Some residual streaking etc. is acceptable.


I’ll probably receive a ton of comments about this next statement but I do not recall, after loading and shooting several thousand rounds of 260 and 6.5 Creedmoor with H4350 did I experience much of a carbon ring issue. It wasn’t until I started using RL-16 in the 6.5 to some extent and the 6 Creedmoor primarily did I encounter this problem. When I look down the bore of my 6 after a string, I swear the bore fouling looks the same as the bore of my Shiloh Sharps 1874 45-70 BPCR. Don’t get me wrong though, I’ll continue to use RL-16 in the 6 Creedmoor along with the other temperature-insensitive Alliant powders but rest assured I’m going to stay ahead of the issue by cleaning much more frequently with a solvent designed for carbon fouling removal. So far I’ve had great luck with Bore Tech’s C4 Carbon Remover, though I’m sure there are other solvents that may do just as well.
If you’re experiencing or suspect a carbon ring build-up in your own match rifle, here’s the component recommended for removal of that stubborn ring.

Stay Safe,
Jim Kauber
Alpha Munitions CSO
President / Director of Training
The Site Firearms Training Center