6.5-284 Norma carbon ring

[RyanG]

I have read that this chambering is prone to getting a carbon ring in the chamber area. I have never seen this until today.... maybe

Can anyone tell me where this ring occurs and can it stop chambering and effect overall length? And whats the best way to clean it?
Thanks

Ryan

[RyanG]

Well I fixed it and it was a bear. I truly do not know what caused it. We had gone to the range yesterday afternoon and were zeroing the rifle and everything was good to go. Then he started to have a hard time closing the bolt on a loaded round. When the round was removed from the chamber it showed huge jam marks on the bullet. I blamed me reloads and we stopped shooting. I got the ammo and the rifle home and measured them. They were all exactly the same length and headspace. But when I checked the seating depth on the rifle using a Frankford Arsenal OAL gauage, that goes on the cleaning rod, I was getting 2.901 overall length. I had his rounds loaded at 3.110. Thats a pretty big difference for me to mess up at the loading bench! I got out my notes from when we started load development and I saw that the original seating was 3.125. I also could not get a Hornady modified case to chamber to check the OAL.

I pulled the barrel and could not see anything obstructing the chamber area but I dont have a bore scope and the flashlight really doesnt do a good job! Well I worked on the chamber area with a nylon brush and carbon remover and was able to remove something because now its right back to 3.125" OAL. I have the barrel reinstalled and headspaced. I pulled the remaining rounds and set them back to new brass numbers and am headed out to the range to rezero it as soon as it warms up a little.

I am still not sure what casued this issue I have never seen anything like it before.

Im sure I did way more work than was necessary but I could just see in the chamber area better with the barrel off.

Ryan

[Texas10]

I went through the exact same experience. I was gob-smacked that I could have made such a huge error in seating depth, only to find I'd measured correctly and the issue was a carbon ring. I use a chamber brush and Carbon Killer. Didn't take long.

To my advantage, I have a bore scope camera. Not expensive but having the ability to look into the chamber and throat is, in my mind, essential to the hand loading enthusiast. Mine is a Snap-On BK5500. Ebay has them for under a hundred bucks.

Some powders are well known to exacerbate carbon build up.

[Slowpoke Slim]

What powders and primers are you guys (RyanG, Texas10) using on those loads? Just curious. I'm using H4831 and Fed match primers, and haven't noticed a carbon ring.

[wn40]

What was the round count since last cleaning did the ring show up? I am using h4831sc with CCI lr primers.

[Texas10]

I was using IMR-4831, 87 grain V-Max, CCI-200, and Federal Brass in a model 11 in 243. It's not my gun, I am helping my shooting buddy work up a load because he isn't seeing any consistency from this gun that was previously a "tac driver".

First thing I noticed is that this particular gun has a very tight, possibly undersized throat. Even after my best cleaning and visual confirmation that the throat is clean and clear of carbon, bullets seated with my Hornaday OAL gage show scratches on the ogive that are too finely spaced to be land marks. And using my bore scope camera, I can see the lands are too far away to be marking the bullet in the area I am seeing the scratches.

I did switch to magnum primers on this particular load, and although that did improve the groups considerably, I have yet to see an improvement in tendency for carbon build up. I suspect a particular combination of powder, heat from a load at or near max velocity, throat dimension, bullet and primer all have a hand in carbon build up. But I have nothing concrete to offer, it's just a theory.

On the bright side, I did take my son on his first ever hunting trip while he is home on X-mas break from college. His gun is a 223 set up for target so we took the 243 and 87 grain load instead.

He took a very nice 8 point mature white tail buck at 220 yds with a shot to the heart. The deer took two steps and collapsed. Head is at the taxidermist, and meat is being processed.

My shooting buddy is overjoyed that his 243 finally took a deer :biggrin-new:

[jpx2rk]

I've read where carbon ring can be found in lots of different chambers/calibers, it's caused by "poor/inadequate cleaning" of the gun for the most part based on my reading. Most don't worry/know about it until a problem comes up like the OP had, clean the gun like the OP did, and all is good. If you can get into the habit of cleaning the chamber more often, it may never happen.

T10's comment above about what causes it is what I've read on several different forums, some powders burn cleaner than others, and then some guns just don't like that powder or combo of components, and the ring starts, and accumulates until the owner has the problems.

Just about every gun forum has similar threads to this one. :(

[RyanG]

Good morning guys,

A quick update on the rifle:

Im only assuming that it was a carbon ring because when I cleaned the rifle I didnt get anything noticeable out of the barrel at one time. I got my "freebore" back a little at a time. (Well I say that but I dropped my Hornady guage and messed up the neck so I had to stop using it.) I took the rifle out to the range and rezeroed it and put about 25 rounds through it with no issues at all. I brought it home and it cleaned up just fine.

Now again I am not positive about it being a ring as when this happened I was not the one shooting. I was standing next to him spotting when I noticed the bolt get hard to close. Im guessing the rifle has had less than a 100 rounds through it since the last cleaning, betting closer to 50. Thats why I was sure it was something lodged in there. This where a bore scope would have saved HOURS worth of work.

I am also using H4831sc with CCI primers. I switched from mag primers to large rifle primers in my 6.5-284 as it gave me better SD's and more consistent groups. This rifle that I am talking about rezeroed and is shooting will under 1/2 inch at a 100 yards. I sure it could get it to shoot even better but it was cold and windy the other day.

I am still at a loss what was blocking there..... Might just have to invest in a bore scope like Texas suggested.....

Ryan