Educate me on this infamous thing called a Carbon Ring.

[Pescetism]

I can't definitively say that this barrel has a carbon ring but I don't know what else would cause the issues I started seeing with ~160 rds on the barrel. Difficultly closing the bolt, circular scuffs on chambered bullets, chambering also seated the bullets deeper, and moderate ejector marks with a load that had up until that point hadn't shown any signs of being significantly overpressure. However, going off velocity it was over 65K. Dropped down over a grain and was still getting ejector marks. The angled mirror tip on my borescope is too large for 22 cal so no worthwhile pictures. Scuffs are smaller after a round of CLR and scrubbing. If there is another cause and/or solution I'd love to get it figured out.

PBB 22 GT .169 FB, Alpha brass, American Reloading "N555", 88 gr ELDM & 90 gr SMK @ 2.500 COAL
LE Wilson full length sizing die w/ bushing and Frankford Arsenal universal seater.
70%/30% suppressed/unsuppressed, and only cleaned for the first 5 shots when new.
No changes in brass prep, loading equipment, or components. Dummy cartridge is still getting scuffs at 2.465.

 

[brazz04]

I had no change in velocity, just started getting ejector swipes from the exact same load over time.

 

[BearGuy]

What combo will give me a carbon ring that will cause these problems? What cartridge?

I will have @longrangelead put one together then I will shoot it as is and see if I can get all these issues from carbon rings…. Because so far with hundreds of thousands of rounds from 223’s, 22CM, 243win, 6cm, 6XC, 6UM, 6.5cm, 260Rem, 6.5-284, 6.5PRC, 25/06, 270win, 270 Weatherby, 7-08, 7mm RM, 7PRC, 7mm STW, 7mm RUM, 28 Nosler, 308, 30/06, 300wm, 300 Weatherby, 30-378 Weatherby, 300 rum, 300 Rum improved, 338 rum, 338 Norma, 338 Lapua- and a whole bunch more… all these problems haven’t showed up.


I just can’t seem to find these issues. Shoot2Hunt has a dozen class rifles that a bunch of posters here have shot and shot next to for 1,200 rounds a week- never cleaned, always suppressed- yet somehow none have these issues. The 223 and 308 barrels have no real functional barrel life- 10,000-20,000 rounds. The 6cm’s last about 2,000 or a bit more. The 6.5cm’s last about 3,000 or a bit more. So on and so forth.


But tell me what the cartridge that will produce failure to chamber, blown primers, etc from carbon rings- I’ll get Mike to spin it up and have students shoot it in every S2H class with 12 witnesses. The last one I was absolutely guaranteed would give carbon rings and cause massive pressure issues quickly was 7PRC. That rifle went over 700 rounds without a single thing but bullets going down the bore, the last two 10x round groups it shot were the two best it ever shot, zero pressure issues, zero functional issues at all and I handed it back to Ryan because I was bored.

I definitely hear what you’re saying and tend to agree with you. With that being said, I’m having a hard time thinking what’s happening in my 6cm right now is something else. I would love to get your opinion on it while it is waiting on my smith to borescope and measure everything else.

Thread 'Barrel Problem'

Thursday at 9:08 PM

Need a little help here. I have a PBB barrel bought from LS Wild last year that might have a problem. Cartridge is 6 creed on a tikka action. When I first got the barrel I felt like the bolt was a little more difficult to close on some rounds then I thought it should be but it shot well and I didn’t really think much of it. I also don’t think I ever chambered a round that I didn’t fire as I was just practicing and getting as many rounds down the barrel as I could. Fast forward to the fall and after chambering a round that I didn’t fire, I noticed some “scratches” on the round. Kind of...

• BearGuy
• Replies: 23
• Forum: Firearms

The info is in this post but long story short I’m getting scratches on all of my bullets and getting ejector marks on my factory rounds and some high speeds with factory ammo and hand loads after ~400 rounds

 

[swavescatter]

I definitely hear what you’re saying and tend to agree with you. With that being said, I’m having a hard time thinking what’s happening in my 6cm right now is something else. I would love to get your opinion on it while it is waiting on my smith to borescope and measure everything else.

Thread 'Barrel Problem'

Thursday at 9:08 PM

Need a little help here. I have a PBB barrel bought from LS Wild last year that might have a problem. Cartridge is 6 creed on a tikka action. When I first got the barrel I felt like the bolt was a little more difficult to close on some rounds then I thought it should be but it shot well and I didn’t really think much of it. I also don’t think I ever chambered a round that I didn’t fire as I was just practicing and getting as many rounds down the barrel as I could. Fast forward to the fall and after chambering a round that I didn’t fire, I noticed some “scratches” on the round. Kind of...

• BearGuy
• Replies: 23
• Forum: Firearms

The info is in this post but long story short I’m getting scratches on all of my bullets and getting ejector marks on my factory rounds and some high speeds with factory ammo and hand loads after ~400 rounds

Easy experiment. Clean your bore very well with the Thorroclean system or C4 Boretech and oversized brass brusshes.

Did the problem go away? If yes, there was some form of carbon fouling that was causing issues (carbon ring). If not, then perhaps you have something else going on with your chamber/ammo.

Form loves to come into these threads and tell people they haven't measured, observed and rectified this "non-existent" issue. Sure, there may be approaches and combos that avoid it, but it's not a myth.

 

[BearGuy]

Easy experiment. Clean your bore very well with the Thorroclean system or C4 Boretech and oversized brass brusshes.

Did the problem go away? If yes, there was some form of carbon fouling that was causing issues (carbon ring). If not, then perhaps you have something else going on with your chamber/ammo.

Form loves to come into these threads and tell people they haven't measured, observed and rectified this "non-existent" issue. Sure, there may be approaches and combos that avoid it, but it's not a myth.

For a 6cm what size brass brush would you recommend?