Carbon Rings and Build-Up in Barrels

Savage 12BVSS

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OK seeking some real insight into this, both cause and effect, without a borescope I'm thinking they can't be spotted very well? What contributes to them? Powder-overbore-or other factors I'm not thinking of?, I'm figuring that rather than the blue/green of jacketing and copper it must be more of a black or dark grey on patches. Just did my major barrel cleaning and match barrels clean to the point of only solvent color on final patches but the two factory barrels seem to still produce that dark discoloration on patches that never cleans up completely. Use barnes cr10 and normal bore solvent's as the final, never use metal bristle brushes but stiff nylon instead. No trouble chambering or with accuracy but some barrels have a few rounds down the tube. Educate me on this subject please and what do's or don't's to employ, I may have no trace of them and my two factory barrels deliver match barrel accuracy but seem to be copper mines compared to lapped match barrels. Dial me in................:)
 

Rardoin

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A carbon ring will build up in the chamber neck area in the space between the end of the case and the transition to the freebore. This ring is only of consequence when it gets thick and hard enough to impinge on the end of the case and possibly contact the bullet (if really bad) and cause pressure spikes. The more insidious carbon ring is a very thin layer of hard carbon built up in the freebore that will cause big pressure spikes and hard bolt closure/ bullets sticking in the freebore on extraction if neck tension is low enough. I use a bronze brush slightly larger than the chamber neck diameter on a chamber brush to clean the former. I use a caliber diameter bronze brush on the same chamber rod in a short stroke pattern to eliminate the latter. I also use a bronze brush to clean the entire bore as my first step in carbon removal using a specific carbon cleaner. I use proper bore guides and high quality bearing handled rods. My barrels are not damaged by the bronze brushes when used in this matter. I also pull the brush back through the muzzle each stroke (OH....THE HUMANITY!!!....LOL). My crowns are not damaged either. Don’t fear a regularly and properly used bronze brush; carbon removal will become a non-issue.
 

Mram10us

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A carbon ring will build up in the chamber neck area in the space between the end of the case and the transition to the freebore. This ring is only of consequence when it gets thick and hard enough to impinge on the end of the case and possibly contact the bullet (if really bad) and cause pressure spikes. The more insidious carbon ring is a very thin layer of hard carbon built up in the freebore that will cause big pressure spikes and hard bolt closure/ bullets sticking in the freebore on extraction if neck tension is low enough. I use a bronze brush slightly larger than the chamber neck diameter on a chamber brush to clean the former. I use a caliber diameter bronze brush on the same chamber rod in a short stroke pattern to eliminate the latter. I also use a bronze brush to clean the entire bore as my first step in carbon removal using a specific carbon cleaner. I use proper bore guides and high quality bearing handled rods. My barrels are not damaged by the bronze brushes when used in this matter. I also pull the brush back through the muzzle each stroke (OH....THE HUMANITY!!!....LOL). My crowns are not damaged either. Don’t fear a regularly and properly used bronze brush; carbon removal will become a non-issue.
You had me until you pulled the brush back thru the muzzle :) Good writeup
 

elkaholic

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I do pretty much what Robin said only I will sometimes saturate a patch with a good carbon solvent and leave it packed in the neck/ throat of the chamber overnight. (usually Kroil)
I ROTATE a bronze brush in the end of the neck to the lead. Its not a bad idea to do this occasionally so it never builds up to begin with.
Also using . 005" trim instead of . 010" or more helps alleviate the problem.
 

L.Sherm

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I would get a Teslong as soon as you can if nothing else to look at your cleaning regime. I dont use Bronzes brushes ive not had an instance yet where its been needed by verification of my borescope.
I clean my barrels like normal then take a patch with Carb out and push it into the neck- throat area and let it sit depending on how bad it is usually if you do it everytime you clean a barrel only takes about 10-15 minutes then rotate a STIFF 1 caliber oversize brush and it comes clean. If its been awhile or never may take longer soaking and more than 1 time.
A borescope is about the only way to tell if your getting it all out.
 
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Wedgy

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I guarantee you have some hard carbon in the throat but just not enough for a negative effect and that is fine, it's only a problem when it gets too big. Put a little JB on a patch with kroil or cleaning solvent and short stoke the throat or first couple inches and you will get carbon on the patch. Some do this as normal preventative cleaning.
 

L.Sherm

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Like Wedgy said if you got atleast 200 rounds on the barrel and have never done it you got a carbon ring, how bad only a borescope will tell you for sure how bad.
JB will get a bad one out better I just don't like using it unless I have to sometimes I get impatient though, ive found staying up on it curses that.
Powders that are dirtier seem to contribute to carbon ring build up faster also.
 

Wolf76

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Had 2 very accurate guns start shooting like garbage, after a few hundred rounds. "Cleaned" them and didn't see any real improvement. Put my borescope in and saw a clean barrel and carbon ring. Tired a number of agents, but Iosso on an oversized brush attached to a drill worked like magic. Both are back to very fine accuracy.
I'm a "dirty barrel" fan for accuracy, but now I clean the throat area every 50-100 rounds. Occasionally the patch even makes it all the way down the barrel 😉🤪.
 

Wedgy

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I'm by no means a barrel cleaning fanatic but I've seen quite a few that got moisture under the fowling and rusted the barrel when stored. I live in the desert so it's not an issue for me but something to be aware of if live in a damp climate or hunt in wet weather. I worked on two brothers 7RM's who ~ never cleaned their guns but one at least oiled his and it cleaned up nicely but the other one is getting rebarreled. Horrible looking barrel with a lot of things going on spraying 18" groups at 100 yards.
 

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elkaholic

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I'm by no means a barrel cleaning fanatic but I've seen quite a few that got moisture under the fowling and rusted the barrel when stored. I live in the desert so it's not an issue for me but something to be aware of if live in a damp climate or hunt in wet weather. I worked on two brothers 7RM's who ~ never cleaned their guns but one at least oiled his and it cleaned up nicely but the other one is getting rebarreled. Horrible looking barrel with a lot of things going on spraying 18" groups at 100 yards.
Yup, the added corroision it causes is often overlooked!
 

Patriot007

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I'm by no means a barrel cleaning fanatic but I've seen quite a few that got moisture under the fowling and rusted the barrel when stored. I live in the desert so it's not an issue for me but something to be aware of if live in a damp climate or hunt in wet weather. I worked on two brothers 7RM's who ~ never cleaned their guns but one at least oiled his and it cleaned up nicely but the other one is getting rebarreled. Horrible looking barrel with a lot of things going on spraying 18" groups at 100 yards.
That's just a dang shame. That's gun abuse 101, LOL:) The $55.00 Teslong bore scope is one of the cheapest most valued tools in my gun room. A must have tool if you care about the well being of your high $$$ toys.
 

26Reload

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I have found that my 65284 barrel shoots best after about 6 shots(after thorough cleaning)...but I only get about 25 shots before it shoots low right then jumps high left....constantly does this...so as they start going low...that rifle is done...
 

L.Sherm

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I have found that my 65284 barrel shoots best after about 6 shots(after thorough cleaning)...but I only get about 25 shots before it shoots low right then jumps high left....constantly does this...so as they start going low...that rifle is done...
Factory or custom barrel?
 

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