6.5 PRC issues

One thing I forgot to say is that I am shooting it suppressed don't know if that matters
The suppressor is speeding up the carbon ring IMO. If you notice how sooty your brass is even down the case body, the back pressure from the suppressor is creating a lot of carbon fouling. A carbon ring isn't a flaw in the chambering job. The fact that it got this bad after 90 rounds isn't an inherent flaw either. If you don't focus on the throat real good when cleaning, and just assume it's clean without scoping it, then a carbon ring will build despite thinking you just "cleaned" it. I'm not knocking you or your practices at all! I dealt with the same thing which prompted me to buy a borescope. Now, when I clean, I focus on the throat and I scope it to make sure the carbon ring is gone. I have two custom barrels that will show a ring like that forming after 120 or so rounds, and I don't shoot suppressed. As a side note, I probably have my trimmer set up a little short which is why mine appears so soon.

It's going to take some work to get that one out, but once you do, it will be much easier during subsequent cleaning sessions as long as you scope it to make sure you got everything out of the throat
 
A carbon ring creating that much pressure after 30 rounds doesn't sound at all normal to me. I had a 28N and it would go 75-100 before the carbon ring would cause pressure.
It begs the question whether OP was thorough during his initial cleanings. OP did you scope it the first few times you cleaned it? He has 90 rounds on it now. I know from experience that thinking your barrel is clean and it actually being clean are two different things.
 
It begs the question whether OP was thorough during his initial cleanings. OP did you scope it the first few times you cleaned it? He has 90 rounds on it now. I know from experience that thinking your barrel is clean and it actually being clean are two different things.
No I didn't scope until I was showing signs. By no means do I think I clean as well as I should. I just have done what I aways have done in the past with my other rifles. Haven't had any issues with carbon ring before so I guess I wasn't to worried about it. The other two rifles I shoot a lot are a 30 nosler and a bergara 6.5 PRC. First time with a CA
 
Expectations for the new 6.5 PRC are sort of excessive. Not a gravity immune cartridge. Same for developed chamber pressures. Clean up barrel with JB and refer to Hodgdon load data with pressures. The throat or leade appears to be sort of rough & uneven as indicated by varying distances of bullet jacket deposits on lands. Try seating bullets back about .003 with factory ammo. Does the fired factory brass allow an easy 6.5 bullet slip fit in to neck?

Brass swipe marks might indicate soft brass (not enough work hardening) and primer flattening & little cratering seems to be reasonable - the primers show a reasonable amount of radius and no indications of gas leaks. Check for primer pocket enlargement. If possible, try another make of ammo/brass.
 
Last edited:
I don't know why people can't read the thread. The OP said he's using factory Hornady ammo which is soft brass to begin with. It's not like he's hot rodding, messing with seating depth, asking miracles of the "new" 6.5PRC. He got a carbon ring which is new to him. It was new to me when I started loading Retumbo in 28 Nosler (coincidentally or not in a CA Ridgeline along with lack of primary extraction). The ejector marks are a known common issue with dual ejector CA bolts and nothing more. CA is also known for lack of primary extraction which could be rearing its ugly head sooner than later because of the carbon ring. CA is also known for cutting their chambers too tight and that along with the whole 6.5 PRC reamer spec vs. brass and die debacle (look it up along with the fix Alex Wheeler made) but I didn't even bring that up because he's shooting factory ammo. The OP should get the carbon ring out and just know that when you start reloading for the caliber, there are issues many have dealt with and be prepared to do some research.
 
Last edited:
No I didn't scope until I was showing signs. By no means do I think I clean as well as I should. I just have done what I aways have done in the past with my other rifles. Haven't had any issues with carbon ring before so I guess I wasn't to worried about it. The other two rifles I shoot a lot are a 30 nosler and a bergara 6.5 PRC. First time with a CA
When I say thorough, I meant verifying what you think you've done. Believe me I had no idea how clean (or not clean really) my bores were until I bought a scope. And that wasn't until after I wasted a bunch of time chasing the same problem you're having now.
 
Send the whole works (rifle, fired brass & ammo lot number) back to the factory uncleaned (dirty) & ask for an explanation of any "carbon ring" problem. CA Ridgeline FFT should know all about "carbon rings". Hopefully, they will install a new barrel, the old one sure looks messed up with only 30 rounds - all those copper fouling deposits on throat & scraped up unfired bullet.

Contact Hornady and ask them about soft brass & if any problems exist with that lot of ammo. Hornady should provide ammo pressures that would be comparable to those listed on Hodgdon site.

Fortunately, I have never had problems like the OP had. I only shoot handloads and my barrels are not factory.
 
Last edited:
Send the whole works (rifle, fired brass & ammo lot number) back to the factory uncleaned (dirty) & ask for an explanation of any "carbon ring" problem.
???

Is this sarcasm?

What would the factory be on the hook for because there's a carbon ring? That's like sending a brand new truck back to the factory because you got a nail in a tire.
 
No sarcasm intended - heavy black fouling & observed radial copper fouling in throat after only 30 rounds fired thru a new barrel would indicate a problem - rough surfaces - this should not happen. The barrel might have been chambered with a defective reamer. Those radial copper deposits are a big concern. Cleaning the barrel would remove any evidence that the event occurred. CA Ridgeline FFT might be able to polish out the rough areas - indicated by those radial copper deposits. The copper deposits are not evenly distributed meaning the throat/lands are not uniform.

I don't believe in "carbon rings" - radial black deposits - yes. These I clean out with a bore foam cleaner, high surfactant motor oil & JB paste (diatomaceous abrasive). Carbon is inert but can be attacked by heat and that would damage a barrel.

No, CA Ridgeline FFT, would not be on the "hook" for a carbon ring but would be on the "hook" for a substandard barrel/chamber job.

Hornady might be asked about that lot of ammo.

Stuff happens.
 
No sarcasm intended - heavy black fouling & observed radial copper fouling in throat after only 30 rounds fired thru a new barrel would indicate a problem - rough surfaces - this should not happen. The barrel might have been chambered with a defective reamer. Those radial copper deposits are a big concern. Cleaning the barrel would remove any evidence that the event occurred. CA Ridgeline FFT might be able to polish out the rough areas - indicated by those radial copper deposits. The copper deposits are not evenly distributed meaning the throat/lands are not uniform.

I don't believe in "carbon rings" - radial black deposits - yes. These I clean out with a bore foam cleaner, high surfactant motor oil & JB paste (diatomaceous abrasive). Carbon is inert but can be attacked by heat and that would damage a barrel.

No, CA Ridgeline FFT, would not be on the "hook" for a carbon ring but would be on the "hook" for a substandard barrel/chamber job.

Hornady might be asked about that lot of ammo.

Stuff happens.
He's shooting suppressed and there are 90 rounds on the barrel. He did clean it but there's no way of knowing whether the most stubborn carbon (that which is laid down right at the end of the chamber) was removed or not because he didn't scope it.

My first experience with a carbon ring happened this way: a known good load went to $**t, ejector marks, hard bolt lift, 100fps higher velocity and…if I chambered a round and then went to extract it unfired…it would pull the bullet out of the case and be stuck in the throat. I'd have to tap the bullet out with a wooden dowel. I checked and rechecked my load specs including powder and seating depth. I referenced my notes on CBTO to touch the lands when I first worked up this load, and when the carbon ring got that bad, that measurement SHRUNK by over .100". It should have grown due to throat erosion. Once I bought a bore scope and spent the next two and a half days scrubbing, the load went back to safe and my CBTO measurement to touch the lands went back to normal. Actually a few thousandths longer than what was referenced from original load development.

You don't have to believe in carbon rings for them to exist and create massive problems. If you prefer to call them "radial carbon deposits," go ahead. But if they get bad enough, they WILL cause problems. It's only logical that if the carbon gets hard enough there to resist standard cleaning practices, then it's hard enough to peel copper off the bullet when you close the bolt. And even hold onto it so tight that it sticks there.

Now, with that said, I'm not trying to be adversarial. So forgive me if it seems like it. I also concede that "stuff" happens. Perhaps the neck of the chamber is a little long, or the brass is a little short. But both of those things are easy to overcome. Just let the brass grow and don't trim until needed. But I don't think that's it. The pictures are blurry, I know, so that makes it hard to see detail. But I don't believe that buildup of carbon which is peeling copper warrants a return to maker, or is indicative of a defective chamber/barrel. It warrants a good cleaning and then staying on top of it, especially if it's going to wear a suppressor all its life.
 
My CA Ridgeline showed the same ejector marks on factory loads during barrel break in. This was caused by solvent in the chamber. The problem disappeared with a clean, dry chamber.

Talked with a gunsmith regarding the pressure signs and he told me that CA chambers have a sharper leade angle that will show pressure signs earlier than chambers with a longer leade angle. He said this design was to help with accuracy, but with trade-offs.

A carbon ring coupled with CA's chambering would explain the ejector marks after 30 rounds.
 
OK. I had similar issues on my CA rifles, a ridgeline and a MPR, both 6.5 PRC. I got a lot of good advice from the guys on the forum, but what ultimately solved my problem was simply seating depth. I was seating my bullets out too far, and that was causing ALL of my high pressure signs. Blown primers, swipe marks on brass, heavy bolt lift, it all went away when I started seating my bullets deeper. No way to tell if that will be the same for you, but try it. I think CA rifles have much shorter throats than a lot of factory rifles do, at least that's my theory. It was an easy fix once I figured it out, and now both rifles shoot VERY well. Hope this helps some.
 
Top