Carbon Carbon!

[chet]

Installed a new Pac-Nor barrel chambered in a 6 BR 8 twist 3 groove, the barrel has approx 80-90 rounds thru it so far, in the beginning during breakin the barrel was shooting very accurate, lately I have been getting groups at 200yds that are terible, I noticed this barrel does not collect any copper, but carbon it does, I am shooting the 107MK with 28 to 28.5 grs of RL-15 or 28.5 Varget. I JB the bore and the carbon is gone, is this carbon build up a common problem with these 3 groove barrels or possibly comming from the load! any cleaning solutions that cut this carbon other than JB

Chet

 

[Jake]

Chet,

I would bet your problem was Carbon fouling. Next time it is shooting those terrible groups, clean the rifle withouth the JB but with a good solvent such as Butches Boreshine. Use a bronze brush as well. The bronze brush will break up most of the Carbon. If you have a lot of that tough Carbon fouling in the throat area, then not even the bronze brush will break it up. This is referred to as the "Carbon Ring". You can find out if you have this carbon ring by taking a damp patch and slowly push it through the bore. If you have carbon built up in the throat you will feel that the throat is tighter than the rest of the bore. Most solvents will not break this carbon ring up even when using a bronze brush, unless you use many stokes with the bronze brush. Two solvents that I've heard that break up carbon better than most is the Slip 2000 Carbon Cutter,Killer?) and Boretech Eliminator. I have not personally tried these solvents, but probably will. So as you have probably found, one of the only ways to get rid of this Carbon Ring is to use an abrasive cleaner such as JB or Iosso bore paste. These cleaners will remove the Carbon ring in my experience by short stroking the throat and the bore a slight amount.

Jake Hayes

 

[chet]

Thanks Jake

I will have to look for the solvents you mentioned, I have tried GM top engine cleaner, It dosen't seem to cut it like JB bore paste.

thanks
Chet

 

[Cochran]

A buddy has a 6.5x284 that stopped shooting. He took it to his smith. The smith wrapped a patch around a bronze brush and coated it with ALOT of Iosso paste. After short stroking it quite a bit he patched out chunks of carbon. He said it went right back to shooting like it did when new.
After one of my 6.5 barrels went south my buddy tried out this technique on mine. No carbon came out. The barrel was just fried but I think its a good idea.
I recently got a look at a couple of my 6mm barrels with a bore scope. My cleaning routine is obviously working well but I did find that I'm leaving some carbon buildup in the case neck area. The soot that I see on the necks of fired cases is also coating the neck area of the chamber and isnt getting touched by the brush. I'm starting to use an over sized brush and a short rod to clean the neck area.

Jeff

 

[Jake]

I also want to say something about the Iosso paste. It turns black whenever you rub it against anything. If you rub it around between your fingers it will turn black. So you can't really use the patches to tell when you have no more carbon fouling.

Jake Hayes

 

[sewwhat89]

Jake, you have carbon fouling on your fingers? :angel:

LOL! j/k

 

[jb1000br]

Chet -- load is too light!

bump up the powder till you see ejector marks and the carbon fouling will dissappear...really

JB

 

[chet]

Hey JB

Longtime no see! I have been shooting alot of black powder cartridge rifles, alot of fun! but anyways about my 6BR, I will have to do some more load testing, If I go above 28.5 of RL-15 with the 107Mk the bolt will get hard to open, this is with the 107's approx .010 longer, maybe if I shorten them .030 it may handle the charge. since I have been away from the highpower world, what powders are popular other than Varget or RL-15 a few yrs ago I tried H4350 and I did get some accuracy but don't recall the velocity.

take care
Chet

 

[jb1000br]

Chet -- Hope you and Chaz can make it back to mifflin

I'd stick with R15...wow...your gun really doesn't like pressure!

What is your velocity at that charge?

JB

 

[Jake]

He says the barrel has 80 to 90 rounds down it, Do you really think it is Carbon fouled???
And he says he's been cleaning it!!!

I really doubt that it is carbon yet. Especially when he says it does not copper foul.... I bet the problem is some where else. A look down it with a bore scope would answer all......
My bet is on a crown problem...... not carbon from a 6BR capacity case in 90 rounds!! Never heard of such a problem that fast from such little powder burned. Best look beyond a carbon build up!! This excessive cleaning may cause more harm then good. That is how a crown can get hurt.
You could also "slug" the barrel and pin point a problem area....

Donovan,

I highly doubt it is a "crown problem" if it only has 90 rounds through it. If you manage to damage the crown after only 90 rounds through the barrel, then you are doing something seriously wrong. My first BR rifle I shot about 3000 rounds by the time I retired that Krieger barrel. I clean my barrels after ever 20 rounds or so. The last aggregate I shot with that barrel,with about 3000 rounds on it) was the smallest aggregate I have ever shot at 100 yards. It was a .20xx with small group at .12x. I would guess I had cleaned the rifle about 150 times up to that point. Furthermore, I use a bronze brush for every cleaning. I don't believe I ever had a "crown problem" after 150 thorough cleanings. I am very careful with keeping the rod straight, and I reverse the bronze brush the instant it exits the muzzle.

However, your guess is as good as mine as to what is going wrong with his rifle.

I use a certain lot of Benchmark in my 6PPC right now that carbon fouls very badly. After a shot, if you pull the bolt out of the action and look down the bore you can see thick black smoke. I use a very hot load that builds alot of pressure, but the powder still burns very dirtily. My normal cleaning routine includes three wet patches of Butches Boreshine short-stroked through the barrel, then about 10 strokes with a stiff Bronze brush, then a few more wet patches of Butches Boreshine, then a few dry patches, then a few drops of oil on a patch. Even with this cleaning routine every 20 rounds, I have found that after about and aggregate I have to use Iosso bore paste to break up the carbon in the throat. I can feel the carbon by running a damp patch through the barrel very slowly. Other powders such as N133 do not carbon foul as much as this certain lot Benchmark so it may not be a problem with other powders. I could go on and on about my observations but it is all anecdotal.

Jake Hayes