Educate me on this infamous thing called a Carbon Ring.

[Wrench]

Powder choice and how the bullet slugs up or what can be called "dwell time" as well as brass fit and throat finish all contribute to induce or reduce carbon. There's been some powders that claim to reduce copper fouling which may have an effect on carbon.

 

[Wrench]

One interesting thing I noticed when re26 was going to be my last powder was that it built carbon but not in the throat, it did so halfway down the barrel.

 

[83cj-7]

One interesting thing I noticed when re26 was going to be my last powder was that it built carbon but not in the throat, it did so halfway down the barrel.

That’s exactly what happened to the guy I know. That was with RL26 as well.

 

[The Guide]

I believe it's mainly a PRC thing. In other words, cartridges designed with tighter than average tolerances. I have a 7PRC and it builds up a carbon ring.

Carbon rings are far from "a PRC thing" as it was common and well known long before the PRC family was born.

Is it due to increased use of suppressors?

I've seen more carbon ring issues on rifles with no muzzle devices than I have on suppressed rifles. Not saying that on some rifles that might not be a contributing factor but the worst I've ever seen was a plain sporter rifle using factory ammo.

My wife had great results in her 7mm-08 with the factory Hornady Superformance load with the 129 SST. All of a sudden, she went from shooting sub MOA 5 round groups to shooting an 8" pattern with 0 consistently. Turns out that the particular load they were using in that ammo was causing carbon rings, inaccuracy, and stiff recoil for dozens of people on the internet when I looked into it. We got the carbon ring removed and tried some of the old ammo and some fresh ammo and that rifle would start showing carbon ring signs again in less than 20 rounds.

We swapped her to a 120 TTSX Barnes factory load and no more issues with that rifle. Unfortunately that rifle is an orphan due to Marlin shutting down and losing support for their bolt action rifles. The biggest issue with the Marlin X7 series was the lack of stock parts. The plastic trigger guard liked to crack and you would lose your action screw torque. I was able to find a metal replacement trigger guard for a different model and machine it so that it would work but it was a process to find that aftermarket piece. Support just doesn't exist anymore.

Jay

 

[Fred@Exterra]

I have a theory that I’d like to test one of these days. I wonder if the new “temperature insensitive” powders are more prone to forming a carbon ring. They use a variety of surface coatings on the powder granules to slow down or speed up ignition. These polymers may not completely combust and re-polymerize in the barrel. So, if anyone has a Gas Chromatography Mass Spectrometer or a Attenuated Total Reflection Fourier Transform Infrared Spectrophotometer laying around & a barrel you wouldn’t mind me sectioning, I’ll get right on it


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[Marbles]

If you're not cleaning your rifle you will have a carbon ring. It might not cause you any problems but it's there. Look in your barrel with a borescope and you'll see it.

I borescoped my 223 after 3,000 rounds without cleaning (edit, over 2,000 with certainty, 3,000 is probably rounding up by a few hundred) and no carbon ring. So, no.

 

[brazz04]

I borescoped my 223 after 3,000 rounds without cleaning and no carbon ring. So, no.

Post the picture

 

[brazz04]

223 at 1047 rounds, never cleaned. But that is 100% a ring of carbon at the case mouth going tot he lands. It causes no issue whatsoever, but it's there.

 

[Axlrod]

@270-300

I’m glad you have good luck with your barrels but believe me, you can shoot out a barrel in short order. There are a lot of factors. Powder, barrel steel, how hot you run it etc. I have shot out a .243 barrel in 600 rounds and a 6x45 barrel in 500 rounds. I believe both of them had something wrong with the steel itself which caused them to burn out quickly. When I say shot out, I’m talking about being able to push a bullet 3/4” up in the throat, like nothing left at all, and confirmed with a bore scope. In my 243 barrels I have found that H4350 was a major factor to killing them too quickly. Now that I have been running H1000, I’m past 2000 rounds with only minor throat wear and a tiny amount of checking.

Good luck? He shoots his rifles 10 rounds per year! It would take like 500 years to wear out a barrel.
Something special about a guy that doesn't shoot, giving advice to guys that do shoot.

 

[Marbles]

Post the picture

Well, it has been posted other threads already.