Carbon Ring
- Thread starter ArtinNC
- Start date
There are a few things that come to mind - and gravity does come into play - but maybe not the way others are thinking (?). I doubt gravity is going to stop a high-pressure flame engulfing the forward chamber from hitting all around the circumference of the exposed area. What might make more sense is a slight amount of solvent or oil from cleaning left in that spot, as it is hard to get a patch into the sharp corner at the end of the chamber. it seems logical that any excess on the patch would have deposited in that area as the patch entered the bore, being a tighter area. If not completely cleaned out, it seems gravity would have possibly left the residue at the bottom of the chamber. Then, upon firing, you get "flame fried" solvent or oil in that spot, being heavier at the bottom of the chamber.
I have tried many bore treatments and cleaners, rust preventatives and the like. One that I vividly recall was called Frog Lube. It left the nastiest crap in my A/R chambers I had ever seen. Any residue also turned my brass black. This kind of reminds me of that. Getting all cleaners or oils out of the chamber, I think, could be your fix. Good luck.
I have tried many bore treatments and cleaners, rust preventatives and the like. One that I vividly recall was called Frog Lube. It left the nastiest crap in my A/R chambers I had ever seen. Any residue also turned my brass black. This kind of reminds me of that. Getting all cleaners or oils out of the chamber, I think, could be your fix. Good luck.
Last edited:
What sharp corner at the end of a rimfire chamber would you be referring to?
TRSR8
Silver $$ Contributor
There is no sharp edge, or shouldn't be.
That fouling/ ring most often forms at the angled leade usually right before full rifling.
Quite common to show initially @ 6 o’clock on many rifles. If left a while, usually migrates 360 deg but even then, often greater on the bottom.
The lead component usually starts it, generally thought to be from undersized lead base expanding hard into bore with initial combustion.
This, all well and good, now easily removed with a soak of C4.
"Sharp edge" was poor choice of words - I thought folks would see that the rifling area of the bore is smaller than the chamber. When pushing the cleaning rod into the bore, solvent puddles can and do form in the chamber as the liquid is squeezed out of the patch on bore entry. If it isn't all removed, it gets burnt. Not that complicated.
A few years ago I still owned many older Winchester 52B rifles of various configurations. Some shot good and others not so well. This was before the advent of bore scopes so I didn't have any idea of the interior barrel condition. I finally bought a Hawkeye bore scope and took a good look at the barrels on all my rifles, paying close attention to the .22's I had. What I discovered was that almost all the older M-52's showed much more barrel wear on the bottom half of the barrel than on the top. In fact several barrels looked almost brand new on the top with deep cut rifling and little to no corrosion present. Then came the obvious question, why was the bottom half of these barrels so cruddy, but the tops so clean? It couldn't be from improper cleaning or else the entire barrel should show more wear. Could it be from inferior ammunition? Don't think so. So why the odd wear pattern?
On a lark I had a cheapo Marlin rifle with a really clean looking barrel. I shot about 100 rounds of various makes of ammunition thru it. I stuck my Hawkeye into the barrel and noticed a bunch of debris on the bottom half of the barrel and a bell went off in my head. Could this be why so many of my older .22 barrels looked the way they did? Damage caused from letting this fouling sit in the uncleaned barrel for who knows how long? So I decided to run my own little test. I put the Marlin in my garage attic for the better part of 9 months. The garage attic is both humid and dry, hot and cold depending on the season. I actually forgot about the Marlin until I went in the attic looking for something else.
I took the Marlin down from the attic and to my work bench and stuffed the boresope in it. It was still dirty, no one had touched the rifle. I cleaned the barrel like I would normally do and wonder of wonders there were all sorts of small little pits in the barrel, but only on the bottom half where all the debris/fouling was located from the last time I shot the rifle. Think about gravity. Those pits weren't there before I put the rifle in the attic. So what did this little test prove to me? Well if you can base it on one rifle barrel it proves that shooting and NOT cleaning the barrel will definitely result in damage to the barrel. Minimal damage, but damage none-the-less. Now do this a couple of hundred times. It also showed even new .22 ammunition can be corrosive. I wish now that I had left the rifle in the attic for a whole year, but I did not. I may take this rifle and re-shoot it and run the test longer, but I think I have proved my point on why so many of my older .22's have half worn out barrels. I should add that there was also a fine spackling of rust in spots on the outside of the rifle because I did not wipe it down before I put it in the attic. I intentionally wanted to see what would happen.
I don't know if anyone else has noticed this barrel oddity on older rifles, especially .22's, but this may help answer why your barrel is rough condition but only on the bottom of it. I kind of lost interest in my small M-52 collection because most of them had this half-worn barrel issue. I ended up selling all but one of them and the one I kept had a very nice looking barrel on it, even on the bottom half.
Rick H.
On a lark I had a cheapo Marlin rifle with a really clean looking barrel. I shot about 100 rounds of various makes of ammunition thru it. I stuck my Hawkeye into the barrel and noticed a bunch of debris on the bottom half of the barrel and a bell went off in my head. Could this be why so many of my older .22 barrels looked the way they did? Damage caused from letting this fouling sit in the uncleaned barrel for who knows how long? So I decided to run my own little test. I put the Marlin in my garage attic for the better part of 9 months. The garage attic is both humid and dry, hot and cold depending on the season. I actually forgot about the Marlin until I went in the attic looking for something else.
I took the Marlin down from the attic and to my work bench and stuffed the boresope in it. It was still dirty, no one had touched the rifle. I cleaned the barrel like I would normally do and wonder of wonders there were all sorts of small little pits in the barrel, but only on the bottom half where all the debris/fouling was located from the last time I shot the rifle. Think about gravity. Those pits weren't there before I put the rifle in the attic. So what did this little test prove to me? Well if you can base it on one rifle barrel it proves that shooting and NOT cleaning the barrel will definitely result in damage to the barrel. Minimal damage, but damage none-the-less. Now do this a couple of hundred times. It also showed even new .22 ammunition can be corrosive. I wish now that I had left the rifle in the attic for a whole year, but I did not. I may take this rifle and re-shoot it and run the test longer, but I think I have proved my point on why so many of my older .22's have half worn out barrels. I should add that there was also a fine spackling of rust in spots on the outside of the rifle because I did not wipe it down before I put it in the attic. I intentionally wanted to see what would happen.
I don't know if anyone else has noticed this barrel oddity on older rifles, especially .22's, but this may help answer why your barrel is rough condition but only on the bottom of it. I kind of lost interest in my small M-52 collection because most of them had this half-worn barrel issue. I ended up selling all but one of them and the one I kept had a very nice looking barrel on it, even on the bottom half.
Rick H.
What you’re seeing at the bottom of the barrel is the fouling left from firing and the next rounds being fired, causing the pits in the barrel it’s not corrosion. Any rimfire barrel is going to get this in the bottom of the bore
This is just forward of where the carbon ring forms
And a non-issue if run two-three dry patches through the bore after cleaning. I have several rifles and I don't think I've ever experienced what you're referring to
Note there is powdered glass or something similar in the priming compound. this is what causes a wear factor in the lead area as well as a build up of vaporized materials in the initial blast. In olden times primers were caustic as well but for the most part we don't have that issue any more. Every time a round is fired a tiny bit of that is dragged down the bore as well as what is left as a deposit 360 degs. ( yep that part is gravity and shows up in the bore scope . seen barrels where is a deposit line almost all the way to the muzzel in some rimfres)
TRSR8
Silver $$ Contributor
My fri
Absolutely not, more so. This because SS is far softer.
Often misunderstood, RF priming requires silicate, i.e. ground glass for detonation.
it lays down on the bottom of the bore…..gets ironed in.
Few years back Eley, bless them, changed up and used a larger silicate substrate and guys had barrels severely hurt in as little as a couple cases with pits until they changed up but all RF match priming results in some impact.
I know, from my own experience, solvents and lubes of certain makes, do, in fact, alter how much carbon is built up. A few products do increase carbon buildup and many decrease it - or at least make it easier to clean the next time. I have no idea whether solvents or lubes had anything to do with this fellow having the carbon ring at the bottom of the chamber or not, but I'll go against the "hundreds" of naysayers from my own practical experience when they say there is no effect on carbon from solvents or lubes. Seems many folks merely repeat what someone else said without doing their own testing. We are entering the "CHATGP" era, as opposed to people figuring anything out for themselves. But what if residue (of any product) at the bottom of the chamber prevented that portion of the chamber from getting as hot during the flash when firing. It could act as a carbon sink, being the slightly cooler spot in the chamber. I do know this to be something that could cause this - but why discount it when one could simply clean the chamber to know for certain?
I found the "undersized bullet" theory interesting. For the carbon ring to form at the bottom only, it would seem there could be a void of heat at the bottom of the chamber (as compared to the top), as carbon tends to build more when the flame is not running (as) hot. But how can that happen when there is flame under pressure in the entire area until the bullet is well down the barrel? From the time a loose-fitting bullet begins to enter the barrel and until it is entirely into the barrel, the "leakage'" of gasses rearward could be directional due to the differences in the barrel grooves. A slightly deeper groove allows more rearward gas in that certain groove until the bullet expands. Lots of interesting things to think about there.
Quoting a part of Searcher's post above: "I found the "undersized bullet" theory interesting."
Searcher, If you haven't read Calfee's stuff, he did a lot of thinking (and writing) about the effects of the carbon ring. He did some pretty wild experiments such as purposely cutting the chamber off center and clocking the barrel where the chamber off set was at 12:00, opposite of where the carbon build up is at 6:00. I don't think he ever arrived at positive outcome on this experiment and ultimately came to the conclusion that the best way to deal with the carbon ring or carbon fouling is to remove it before it builds up to the level where is affects accuracy. That is what you see most benchrest rimfire shooters doing between cards - cleaning out the carbon/carbon ring. From my own personal experience, shooting a rifle with a Shillen 4 groove barrel, If I don't clean mine between cards, by the end of the second card I start to get flyers.
He also wrote that concentrating on cleaning the 1st few inches of the barrel past the chamber was more important than cleaning the full barrel, although it gets swept out as you push the patch all the way out when you are cleaning the barrel.
Anyway, if you did not already have enough to think about, reading Calfee's thoughts on the subject may give you a different perspective on why you should be concerned about the carbon ring in a competition match barrel. I believe mass produced rifle barrels are much more forgiving about carbon rings and cleaning in general, and some actually improve accuracy after developing a carbon ring, until it gets too big and starts to affect accuracy negatively. Calfee called this the "accuracy window". Now I guess I will see how big a fit TRSR8 throws for mentioning Calfee.
Searcher, If you haven't read Calfee's stuff, he did a lot of thinking (and writing) about the effects of the carbon ring. He did some pretty wild experiments such as purposely cutting the chamber off center and clocking the barrel where the chamber off set was at 12:00, opposite of where the carbon build up is at 6:00. I don't think he ever arrived at positive outcome on this experiment and ultimately came to the conclusion that the best way to deal with the carbon ring or carbon fouling is to remove it before it builds up to the level where is affects accuracy. That is what you see most benchrest rimfire shooters doing between cards - cleaning out the carbon/carbon ring. From my own personal experience, shooting a rifle with a Shillen 4 groove barrel, If I don't clean mine between cards, by the end of the second card I start to get flyers.
He also wrote that concentrating on cleaning the 1st few inches of the barrel past the chamber was more important than cleaning the full barrel, although it gets swept out as you push the patch all the way out when you are cleaning the barrel.
Anyway, if you did not already have enough to think about, reading Calfee's thoughts on the subject may give you a different perspective on why you should be concerned about the carbon ring in a competition match barrel. I believe mass produced rifle barrels are much more forgiving about carbon rings and cleaning in general, and some actually improve accuracy after developing a carbon ring, until it gets too big and starts to affect accuracy negatively. Calfee called this the "accuracy window". Now I guess I will see how big a fit TRSR8 throws for mentioning Calfee.
TRSR8
Silver $$ Contributor
TRS doesn’t throw a fit for mentioning Calfee. Much of what’s referred to and recalled is dated, wrong, or misrepresented, pretty easy.
Like any other human he got stuff right, he got stuff wrong and unfortunately took credit for some stuff he flatly did not deserve.
Fair amount in that book has been shown to be incorrect and before you respond, I knew him well, used to converse regularly for years and owned a national championship BC rifle.
P.S. you know how many of those experiments were claimed simply to throw gullible fools into believing almost anything.
Tell us, why don’t you, how you cut an off center chamber in a barrel chucked up in a lathe. That there is some masterful machine skills.
Last edited:
I knew that wouldn't take long.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.