Copper issue.

[Nude nut]

I have a true flight 1.9 twist 34in chambered 300 norma with a serious copper issue.
The barrel has 180 rounds through it and the copper is the full length of the barrel with naked bullet and about two thirds when using moly coated bullets.
I have used true flight barrels for years in my match barrels and never had this issue before they very rarely get copper at all.
Now I thought that the issue maybe the long bearing surface on the 230 berger hybrid I have run them from 2980fps to 3100fps same result.
I have polished the barrel 3 or 4 times no change I thought it maybe barrel lenght but im not so sure on that looking at info around on the 300 norma.
Im going to make up some lead plugs give it a serious lapping to see how that goes so any thoughts or input would be good this barrel takes about 3hrs to get copper out but still needs an abrassive to get the last copper remains out.

Cheers Trev.

 

[Coyotefurharvester]

How many rounds fired until accuracy changes?

 

[Nude nut]

How many rounds fired until accuracy changes?

Have not shot more than 20 rounds before cleaning but accurcy is fine at tha round count.
I have been load testing at 900yrds at the present no fliers but even after 5 shots its chockers full of copper I have never seen anything like this before.
For the amount of copper thats in there I wouldht be surprised if the bullet started playing up on the way to the mile mark.

Cheers Trev.

 

[jelenko]

Do you have a borescope? From my limited experience, copper in a new barrel comes from tooling circular tooling marks just before the rifling starts.

 

[Nude nut]

Do you have a borescope? From my limited experience, copper in a new barrel comes from tooling circular tooling marks just before the rifling starts.

yes I have borescope it looks fine the barrel is a ultra match barrel it looks just like my comp barrels inside and this is what has me stummped.
I borescope all my barrels before I get them chambered use same gunsmith who does fine work.

Cheers Trev.

 

[FNSafari]

I have a true flight 1.9 twist 34in chambered 300 norma with a serious copper issue.
The barrel has 180 rounds through it and the copper is the full length of the barrel with naked bullet and about two thirds when using moly coated bullets.
I have used true flight barrels for years in my match barrels and never had this issue before they very rarely get copper at all.
Now I thought that the issue maybe the long bearing surface on the 230 berger hybrid I have run them from 2980fps to 3100fps same result.
I have polished the barrel 3 or 4 times no change I thought it maybe barrel lenght but im not so sure on that looking at info around on the 300 norma.
Im going to make up some lead plugs give it a serious lapping to see how that goes so any thoughts or input would be good this barrel takes about 3hrs to get copper out but still needs an abrassive to get the last copper remains out.

Cheers Trev.

Some barrels just take time to break in and wear down the tooling marks from rifling even though they may have been lapped. How does it shoot?

 

[L.Sherm]

You said you've polished the barrel 3 or 4 times, the whole length of the barrel?
There is such a thing as to smooth of a bore.

 

[Nude nut]

Some barrels just take time to break in and wear down the tooling marks from rifling even though they may have been lapped. How does it shoot?

It shoots well but I thought after a 120 rounds or so it would ease up on the copper its not behaving like all my other trueflight barrels.
Maybe the 300 norma is a different animal.

Cheers trev.

 

[Nude nut]

You said you've polished the barrel 3 or 4 times, the whole length of the barrel?
There is such a thing as to smooth of a bore.

Yes could be the case I may just shoot it until its accuracy falls off then clean.

Cheers Trev.

 

[FNSafari]

It shoots well but I thought after a 120 rounds or so it would ease up on the copper its not behaving like all my other trueflight barrels.
Maybe the 300 norma is a different animal.

Cheers trev.

Once you fire the first shot through a clean barrel its got copper. Does the cu buildup over the number of shots you want to fire before cleaning affect accuracy?

I see where truflight is a nz company and am not familiar with them and their finishing methods. You prolly should talk to them about it. Does it borescope rough, with tool marks and inclusions? If so, definitely call them on it. If its supposed to be a BR quality barrel you should not see those things.

 

[Nude nut]

Once you fire the first shot through a clean barrel its got copper. Does the cu buildup over the number of shots you want to fire before cleaning affect accuracy?

I see where truflight is a nz company and am not familiar with them and their finishing methods. You prolly should talk to them about it. Does it borescope rough, with tool marks and inclusions? If so, definitely call them on it. If its supposed to be a BR quality barrel you should not see those things.

Your right I shoulnt be seeing this And I never have in my comp barrels in 223rem,6.5x47 and 308win so I expected the same.
Some have said pushing big heavy bullets will do this but I have scanned many posts on the 300 norma and only seen a few cases but not as bad as this.
Some switched to the 230 atip and problem ceased Im not so sure on that.
I dont shoot long strings with this rifle most would be 10 rounds in a controled manner I have shot 30 rounds over a period of 2hrs inbetween shooting other rifles the accuracy holds true.
But when you give it a clean man it takes a good 2to3 hours to get the copper out the carbon is no problem.

Cheers Trev.

 

[Kurz]

You prolly should talk to them about it.

There is no doubt about this, call first, of course but I recommend taking a few borescope photographs and sending those along with a description of your shooting process and your cleaning process. They may be able to help by remote but do not hesitate to remove that barrel and ship it to the manufacturer for them to assess.

 

[FNSafari]

Your right I shoulnt be seeing this And I never have in my comp barrels in 223rem,6.5x47 and 308win so I expected the same.
Some have said pushing big heavy bullets will do this but I have scanned many posts on the 300 norma and only seen a few cases but not as bad as this.
Some switched to the 230 atip and problem ceased Im not so sure on that.
I dont shoot long strings with this rifle most would be 10 rounds in a controled manner I have shot 30 rounds over a period of 2hrs inbetween shooting other rifles the accuracy holds true.
But when you give it a clean man it takes a good 2to3 hours to get the copper out the carbon is no problem.

Cheers Trev.

I've shot my 338 Win Mag with 225 gr Hornady GMX bullets, solid guilding metal and see no excessive copper from them. My Browning/FN barrel cleans up with reasonable effort. Those are long bullets for their weight., lots of bearing surface.

 

[David Milisock]

I have a true flight 1.9 twist 34in chambered 300 norma with a serious copper issue.
The barrel has 180 rounds through it and the copper is the full length of the barrel with naked bullet and about two thirds when using moly coated bullets.
I have used true flight barrels for years in my match barrels and never had this issue before they very rarely get copper at all.
Now I thought that the issue maybe the long bearing surface on the 230 berger hybrid I have run them from 2980fps to 3100fps same result.
I have polished the barrel 3 or 4 times no change I thought it maybe barrel lenght but im not so sure on that looking at info around on the 300 norma.
Im going to make up some lead plugs give it a serious lapping to see how that goes so any thoughts or input would be good this barrel takes about 3hrs to get copper out but still needs an abrassive to get the last copper remains out.

Cheers Trev.

Is this a new lott of bullets? Have you shot this lot of bullets in any other rifle?

 

[Nude nut]

Is this a new lott of bullets? Have you shot this lot of bullets in any other rifle?

these are the only bullets shot through this barrel from break in to 180 rounds they were purchased when barrel was chambered .
I havnt shot these bullets in any other rifle.

Cheers Trev.

 

[Nude nut]

I've shot my 338 Win Mag with 225 gr Hornady GMX bullets, solid guilding metal and see no excessive copper from them. My Browning/FN barrel cleans up with reasonable effort. Those are long bullets for their weight., lots of bearing surface.

I dont think its the bullet weight I cant see any reason that thats the problem I even loaded lighter powder charges to see if speed had any affect but no difference.

Cheers Trev.

 

[Nude nut]

There is no doubt about this, call first, of course but I recommend taking a few borescope photographs and sending those along with a description of your shooting process and your cleaning process. They may be able to help by remote but do not hesitate to remove that barrel and ship it to the manufacturer for them to assess.

Yes I leaning that way going to visit gunsmith next week.

Cheers Trev.

 

[FNSafari]

I dont think its the bullet weight I cant see any reason that thats the problem I even loaded lighter powder charges to see if speed had any affect but no difference.

Cheers Trev.

Bullet length determines the barrel twist rate you need, not weight. Good luck with the barrel maker.

 

[BoydAllen]

Barrel makers use coarser grit than you might expect to put the final finish on their barrels. If you polish with fine grit, to a finish that is too smooth, you will make the problem worse.

 

[Nude nut]

Bullet length determines the barrel twist rate you need, not weight. Good luck with the barrel maker.

I know this was just using weight of bullet most of the people here know heavy bullets have long bearing surface my bad.
I have had to send 1 barrel back in the past but that wasnt without some stern comments from myself when they tried to play the game.

Cheers Trev.