Carbon ring

arch408

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Joined
Dec 6, 2012
Messages
412
I've got a relatively new 7 WSM Bartlein barrel on a custom action. The barrel has about 500 rounds on it and has been cleaned regularly. It was never shot hot. The barrel is loosing accuracy fast and nothing seems to help. I took a look through the bore scope and found a jet black carbon ring at the end of the chamber.

I took a bore mop and soaked it with Bore Tech carbon remover and left it sitting against the ring for two days. I refreshed the carbon solvent several times. The ring appeared unchanged. I put a bronze brush on a short rod and tried to spin some of the carbon off thinking that it was probably soft after the soaking. Oddly enough, the black rings still looks about the same.

Any suggestions?
 

MagnumManiac

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Feb 25, 2008
Messages
3,799
You can learn from this that it's best to manage on a regular basis, never letting it build up.
You can also mitigate it's formation with tight end clearance(10thou max) instead of trimming far short.
But IMO, it'll be pretty hard to demonstrate this as the cause of your accuracy falling off. It would have to be so bad as to cause potentially hazardous pressure spikes to see it on target.

Somebody needs to offer an extended end mill for this task. Like Sinclairs primer pocket uniformer,, only for chamber neck and extended 10" to a handle.
I use my pistol cleaning rod, it is 12” long without the brush attached.
I have found JB works in short stroking, but using a tight nylon brush spun in a cordless works faster and it’s turning with the cutting marks left in the chamber.
I have never seen any damage doing this.

Cheers.
 

Hugnot

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Sep 26, 2020
Messages
635
Location
Montana
My cleaning routine is to fill the barrel with GunSlick foaming bore cleaner and let it soak over night. Then push the foam, now blue-black glop, out with a patch, followed by 20 or so strokes of a nylon brush dipped in 5-20W synthetic, high detergent (surfactant) motor oil. Any remaining crud gets attacked with JB (garnet abrasive) then more motor oil and patches. Carbon, if present, is insoluble (inert), and only can be attacked with heat and that would do a number on your barrel. Any black stuff is probably a mixture of powder and primer residues (lead) with some carbon. The foam seems to break up the black stuff & detergent motor oil seems to float it away & the JB seems grind it down. Stainless steel undergoes some oxidation with heat, forming chrome oxide and that might contribute to less than sparkling bores.

Gunslick foam, 5-20W synthetic, & J-B have been wiped off (paper towels) my nice wood stocks for as long as I can remember without consequences. Wearing nitrile gloves while cleaning barrels might be a good idea.
 
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Coldfinger

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LRH Team Member
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Feb 20, 2020
Messages
1,067
Location
NY
Does it look dull or shiny? It may not be a carbon ring, but carbon in the haze cracking at the end of the chamber.
I use a nylon brush a little bigger than normal, a cal larger, plenty of carb cleaner and spin it up fast in my drill. Alternating between carb cleaner and CLR.
You need a carbon solvent, brake clean, carb clean and CLR all work extremely well.
DO NOT GET ANY OF THEM ON YOUR STOCK FINISHES, BLUEING OR PLASTIC.

Cheers.
P.S.
Expect to replace your nylon brush after this, it will melt.
Heed his warning about getting those chemicals on synthetic stocks!
 

The Oregonian

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Jul 20, 2012
Messages
1,669
Location
Missoula, Montana
No just put it on a short rod and turn it slowly just as you engage the lands.. You can use a drill but, caution you could damage your bore if patch happened to come loose. I would say if your going to use a drill do it with your brush, Nylon preferred.. after the IOSSO use some kroil oil for a a hour to loosen it up and then hit it with the brush.
I use a drill, nylon brush with a patch wrapped around it, and iosso. I do it very carefully and not very long for each run, checking in between.
 

DJ Fergus

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Joined
Dec 25, 2015
Messages
2,879
Plug your muzzle with a foam ear plug. Fill bore up to the chamber with bore
Tech carbon remover with rifle vertical. Let it set for 7-14 days and make sure it stays full. Drain and go to work with a brush. It shouldn't take long to get the carbon out after this.
 
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