My bloody luck

[Sambo]

So my first foray into 7mm isnt being as easy as one might expect. Ive finally got all the gear sorted and trimmed donuts from cases so they dont affect me, Ive had my barrel recrowned as one land edge got rolled over (my bad) but now I have a 30 inch krieger 5R 1:8.5 twist that is coppering hard from the start of the throat all the way to the crown. Just ticked over 450 rounds today and with a clean barrel (borescoped) it took all of 5 shots to start spraying them. Its the 4th krieger Ive owned (various cals) and none have set the world on fire. Weird thing was I didnt get much copper in the run in of the barrel, now it looks to be a worthwhile investment for Clive Palmer if he ever wants to open a copper mine.

I know enough about the mining industry to know that Clive would definitely be more interested in trimming your donuts than mining your barrel.

[Brad Y]

Possibly it was the carbon making it look like firecracking. If I could see a 3D close up image of the rifling it would be easy to see it as a crack or as a carbon ridge. But borescopes dont go into that detail. Anyway its shinier than it has been for a while and its not picking up that copper. Ive had glazed on carbon in a barrel before and it filled the grooves and was all over the lands as well. This copper fouling was picking up when I could still see silver in the grooves. Interstingly it was on the canted sides of each land and not on top. Iosso apparently wont take steel out so Im fairly certain its just removed carbon patterning on the lands.

Moly seems to have a false rep of giving you faster projectile speed, though never using it before, in all the experience of people I would trust, for a given powder charge they generally see a decrease in speed but are able to increase powder to get back to that velocity. Maybe it does reduce pressure to get to a velocity a little. I have another plan first to try before I try moly paste in the bore or moly coated projectiles.

James, would love to know what you are using and the routine to keep your guns clean.

[DaveMc]

Brad, I hadn't seen firecracked/crazed Carbon till last Sunday

I've cleaned a few rifles recently where the carbon pattern as you describe is evident.
Usual application of one pass of aluminum oxide around 500grit on a patch wrapped around a nylon brush, sometimes a second pass, flush out, oil, wipe out then shoot.
The carbon issue starts when shooters don't clean their rifles after shooting the last range.
Instead, after having a few beers, they go home with the best intentions of cleaning the rifle but other commitments mean it's mid week or the next shooting day before the barrel gets a wipe out.
By that stage, the carbon has gone hard and you will need a paste to get it out.
In most cases, the shooter does a cursory clean and because the carbon is hard, no black will show on the patches and they think there barrel doesn't foul.
Next layer of carbon goes on top and a few weeks later they are struggling to get a score on the target

+1 on James' comment here. I have also noticed this first hand (with borescope) and seems especially bad with 2213SC in a hot cartridge (e.g. 243AI, 6.5*284 etc). No problem if you clean it out every day immediately after shooting but don't let it cool down and build layers upon layers. It builds up thick in the throat area (can feel with pilot bushings on range rod) and gets hard to remove. I believe it can actually act like a "swage" in the throat resulting in the projectile having a loose, poor fit for rest of travel down barrel and engraved in shapes nothing like the rifling - effectively acting like a worn muzzle or badly lapped barrel. We really like things narrowing toward the muzzle or at least straight through.
You will get carbon that looks firecracked and not long after this I believe it will start to "peen" or move the metal with it. I have destroyed a couple of barrels apparently early in their life and looks like firecracking. I am not convinced all firecracking is firecracking or rather possibly some compression effect like this but I may be wrong. Anyway - taking the time to clean regularly whilst warm has helped immensely and barrels look and hold together completely differently. I know some swear by shooting whole queens without cleaning but this is not for me. Also some swear you will destroy a barrel by overcleaning.
So not everyone will agree with this......and really it is just observation and no fact.
Cleaning regimes are many and varied and it is a process of listening to everyone and trialling a few and determining what works best for you.

I am happy with what I do now and clean every day and sometimes a quick scrub after a couple of ranges.

[Brad Y]

Well fingers crossed this is the start of the solution and the barrel will come good with some more load work. If not, maybe that much fouling early in the barrels life has affected it detrimentally and its not going to happen. Will find out over the next few hundred or so I guess.

[ecomeat]

My own Maddco 7mm experience that i related was with 100% 2213sc.
Tony

[Triplejim]

James, would love to know what you are using and the routine to keep your guns clean.

http://www.triplej.com.au/productpages/barrelcleaning.htm
I amend this from time to time as I trial various cleaning compounds.
When all else fails, simply go back to solvents that have withstood the test of time.
Hoppees No9 and Sweets Oil are two that come to mind.

[Triplejim]

I believe it will start to "peen" or move the metal with it.

I've experienced this phenomena with a tight 3065 x 2975 Obermeyer barrel.
The barrel appeared to get grabby on the patch but didn't disappear after applications of JB paste.
This was before the days of borescopes so I've no pictorial records.
However, in discussion with the late Jim Reither, he recommended lapping the lands to even out the metal shift.
The lap was a 4" long rod around .298" with a 3 or 4 circular grooves to which he applied valve lapping paste.
He started at the leade and worked up the barrel until the lap went full length, took about 10 minutes.
Barrel was returned to its former glory.

[RAVEN]

Ecomeat spot about the KG

KG1 can be substituted with any carby clean or top engine cleaner
The KG2 is a great product that will maintain the any build-up of carbon nand is not too abrasive
JB is OK but I wouldnt go to hard with it

The bore MUST be degreased (removal of any petroleum based oil or solvent)
before using KG12
I use KG products as a barrel cleaning system and maintain consistent bore condition with Hoppes No.9 during events.

James your comment are spot on as well
I must say I'm one of those that cleans some days later but your advice of cleaning at least the carbon as soon as possible after shooting is good advice especially for those barrels that tend to fowl quicker.

RB

[jcinsa]

I only have experience with 308's,


I run in my barrels in with Hoppes no 9 to get the carbon out, and KG 12 to remove the copper.

Once they're run in, all I every do is Hoppes no 9 with a bronze brush a couple of times, and dry patch it out, after shooting each day.

If I'm not shooting the next day I put some sweets oil in the barrel which is patched out prior to shooting.

My Kreigers treated like this clean up beautifully, and are very predictable after cleaning.

Trevor Deed told me when I first started " don't over clean your barrel", and it was very sound advice.

He was dead right, any more cleaning than this and the barrel takes too long to settle down.

John

[DaveMc]

I only have experience with 308's,


I run in my barrels in with Hoppes no 9 to get the carbon out, and KG 12 to remove the copper.

Once they're run in, all I every do is Hoppes no 9 with a bronze brush a couple of times, and dry patch it out, after shooting each day.

If I'm not shooting the next day I put some sweets oil in the barrel which is patched out prior to shooting.

My Kreigers treated like this clean up beautifully, and are very predictable after cleaning.

Trevor Deed told me when I first started " don't over clean your barrel", and it was very sound advice.

He was dead right, any more cleaning than this and the barrel takes too long to settle down.

John

John, I should point out my "overcleaning" daily is exactly what you just described.

[BRETT B]

I have Run Hot calibres (22-250 ack, 243 ack, 260ack) all my shooting life and my cleaning regime has always been, shoot no more than 3 ranges then CLEAN!!! People used to say i would wear the barrell out cleaning it but all the barrels i cleaned well and especially concentrated on getting the carbon out seemed to last a hell of a lot longer than most others using the same calibre/cartridge combo. I have also found that when using ADI powders in hot or overbore cartridges that its easy to get fast hard carbon build up from the high flame temps ADI powders can produce if running the load a little warm with powders on the fast side for the calibre.

[Brad Y]

See I find running slightly faster powders and a bit more pressure to be better than running a slower powder. 2209 at high pressure seems to burn cleaner than 2213sc running the same velocity. The trouble lies where 2209 shoots well but burns dirty but is accurate then you shoot 2213sc for slightly better velocity its dirtier again, but going back to 2209 and more powder it hits pressure limits before you can get into the next node.

Anyway powders aside, the barrel is alot cleaner with no more 'alligator skin' and less copper being picked up. Time to shoot some groups and see what it can do.

[BRETT B]

Brad , in my experience with 2209 it seems to work the best from a cleaning perspective when you run it in the mid range of velocity forthe cartridge you are using. I always use it to fireform ackley cartridges with a mild load of 2209 and it shoots great and doesn"t carbon up at all!! but then put it in a full power load and turn the throttle up just a bit and its flame temp gets high and you gat carbon bake real quick!! It does depend on cartridge /calibre combo and some barrels do it worse than others but its what i have found with my barrels over the years using 2209.

[jcinsa]

No worries Dave, I agree with what you said.

Cleaning too much copper out ( of the pores ) is what I was meaning, by 'over' cleaning ( especially with products like KG 12 ).

Ensuring you don't get 'ceramic' carbon build up is what I think is most important.

John

[RAVEN]

It my View that 2213SC is effected by humidity there is definitely an trend not to use it up north.