Gunsmithing Krieger barrel fouling badly with Barnes TSX

[Jpat]

I have a Krieger barrel in 7 SAUM that has about 270 round through it. I've been shooting Barnes TSX 160 FB as a hunting round. Barrel has been throated long and I'm running a Bighorn SR3 with Wyatt cut and extended Wyatt mag box. The issue is that after about 20 rounds im getting excessive cooper fouling over a 6 or 7 inch distance midway down the barrel, (borescoped). Everywhere else the copper fouling is minimal. After 20 rounds or so velocity starts creeping up and group size increases. Velocity measured with Magnetospeed jumps about 30-40fps. Looks like the copper fouling is sufficient enough to constrict that portion of the barrel enough to increase pressures. Has anyone experienced this with a custom barrel? Some of my other barrels will take way more rounds before needing a scrub.

 

[__JR__]

Did you call Krieger?

 

[Praeger]

Slugging the barrel would be the next step, although I'd contact Krieger and give them a chance to check it first.

 

[Brux]

I had this problem in the last 5 inches of a different brand well known barrel. They replaced it.
My experience with Barnes bullets is that they copper foul any kind of barrel so I don't use them.

 

[Thud]

I had this problem in the last 5 inches of a different brand well known barrel. They replaced it.
My experience with Barnes bullets is that they copper foul any kind of barrel so I don't use them.

Same here

 

[__JR__]

Used to work with barnes bullet combos a lot in a former life. If I knew the customer was specifically shooting x ammo, would contemplate with said customer adjusting the groove diameters to suit, and perhaps use more of the old school military throat with only throat and no freebore. Example, for 308 rather than .3085 max wed look at .3088 which technically is still spec but CIP rather than SAAMI. Rather than a Win style freebore, went for the '06 straight taper throat. Barnes did foul less when I did this..

 

[__JR__]

Used to work with barnes bullet combos a lot in a former life. If I knew the customer was specifically shooting x ammo, would contemplate with said customer adjusting the groove diameters to suit, and perhaps use more of the old school military throat with only throat and no freebore. Example, for 308 rather than .3085 max wed look at .3088 which technically is still spec but CIP rather than SAAMI. Rather than a Win style freebore, went for the '06 straight taper throat. Barnes did foul less when I did this..

But regardless, in my discussions with customer I would put out the disclaimer: You do realize for foulness, barnes is a Saigon whore. So you're going to need to up your game on bore keep.

 

[FisherT&C]

This could be a lapping issue. If the bore is too smooth it puts too much pressure on the bullet causing excessive fouling. Removing the copper then a light lapping may fix the issue.

 

[Bugholes]

its been my experience that when a barrel copper fouls in the middle of the barrel you may need to have the barrel re-lapped or you may need another barrel
copper on the muzzle end is a different story

 

[Clark]

I bought some boxes of TSX bullets, but the Copper fouling was too much for me to deal with.
I buy barrels from Bartlein, Krieger, Lilja, Shilen, Pac Nor, Benchmark, Douglas, Hart, Lothar Walther, etc.
All premium lapped barrels will go longer without fouling than a budget barrel.
I use IMR-4166 in long actions and CFE223 in short actions. They have some anti Copper fouling coatings.

 

[__JR__]

This could be a lapping issue. If the bore is too smooth it puts too much pressure on the bullet causing excessive fouling. Removing the copper then a light lapping may fix the issue.

no one laps that smooth

 

[__JR__]

its been my experience that when a barrel copper fouls in the middle of the barrel you may need to have the barrel re-lapped or you may need another barrel
copper on the muzzle end is a different story

I'm with you on that.

 

[FisherT&C]

no one laps that smooth

not on purpose.

 

[Chicory01]

I had this problem in the last 5 inches of a different brand well known barrel. They replaced it.
My experience with Barnes bullets is that they copper foul any kind of barrel so I don't use them.

I have a Krieger barrel in 7 SAUM that has about 270 round through it. I've been shooting Barnes TSX 160 FB as a hunting round. Barrel has been throated long and I'm running a Bighorn SR3 with Wyatt cut and extended Wyatt mag box. The issue is that after about 20 rounds im getting excessive cooper fouling over a 6 or 7 inch distance midway down the barrel, (borescoped). Everywhere else the copper fouling is minimal. After 20 rounds or so velocity starts creeping up and group size increases. Velocity measured with Magnetospeed jumps about 30-40fps. Looks like the copper fouling is sufficient enough to constrict that portion of the barrel enough to increase pressures. Has anyone experienced this with a custom barrel? Some of my other barrels will take way more rounds before needing a scrub.

I bought some boxes of TSX bullets, but the Copper fouling was too much for me to deal with.
I buy barrels from Bartlein, Krieger, Lilja, Shilen, Pac Nor, Benchmark, Douglas, Hart, Lothar Walther, etc.
All premium lapped barrels will go longer without fouling than a budget barrel.
I use IMR-4166 in long actions and CFE223 in short actions. They have some anti Copper fouling coatings.

How did the copper fouling from Barnes TSX effect your accuracy?

Are we talking going from 1 MOA to 3 MOA or 1 MOA to 8 MOA?

 

[MikeMiller]

It’s the copper bullets. Had the Barnes foul every barrel I have tried in

 

[Chicory01]

It’s the copper bullets. Had the Barnes foul every barrel I have tried in

How bad was the after effect? 1 MOA to 3 MOA? 1 MOA to 8 MOA?

 

[MikeMiller]

My memory is old and it’s been years since I gave up on them but memory is terrible groups of over two moa