Experts please advise: inexplicable barrel fouling - affecting accuracy - "lumps" in lands

[zambezi]

Fire cracking happens, seems a bit soon in this case but have you tried a few patches of JB compound to smooth the rough out? At this point it may help.

Have you tried JB bore compound yet? Very quick and easy to use.

But you obviously do have a rough bore. So give JB a chance.
I'm not proposing that you make it a regular routine, but every 500 shots or so definitely won't kill your barrel. It's a proven product, despite all the snake oil gossip on the internet.

Youve got to try JB, nothing else comes close.

JB, JB, JB...

Suggest giving it a seeing to with JB borepaste

I have exhausted all possible non-abrasive cleaning regimes. But this barrel [once all copper is removed] is too good to bin .

All I need is to: fix the accelerated copper fouling which causes loss of accuracy after just 15 shots.

The J-B paste remediation of this barrel begins...

 

[C h r i s]

At last! Good man

 

[zambezi]

Before I start smoothing the throat and bore with J-B, I have captured the current status in images so that I have a before-n-after visual to accompany the range derived data.

In sequence the leade , the first portion of the throat ,example of pits which are clustered radially 4cm ahead of the forend and the crisp crown .

Next post shows the first 8cm of barrel in sequence from leade through the throat...

 

[C h r i s]

intereted to see what it does to the firecracking (or what appears to be)

 

[zambezi]

...images of the throat for completeness. Images taken roughly 1cm apart progressing down barrel.

 

[Alantoo]

intereted to see what it does to the firecracking (or what appears to be)

It has come up a few times on here...please note the difference between double thumbs up....and giving a double finger smiley...

Of course if you did mean "swivel" my apologies...

Alan

 

[C h r i s]

Ah yes well spotted, edited now lol

 

[zambezi]

First run with J-B was principally to address the hideous cracking in the throat.

This roughness must surely be the cheese-grater-stylee intitiator of the copper deposition that builds up so quickly in a cleaned barrel.

Not sure I can 100% quantify any land edge profile smoothing, but faces are definitely cleaner.

I planned to test accuracy on Wednesday, but the met office now declares 50mph winds at the range so perhaps I should not focus on groups. However, I can still test whether copper build-up has been attenuated.

...

 

[zambezi]

...

 

[C h r i s]

Keep scrubbing!

 

[HandB]

...View attachment 205998 View attachment 205999

It still looks like there is a lot of hard carbon remaining. When I am using JB bore paste on my rifles I scrub them until the steel is visible.

 

[muddy42]

I would keep going, maybe alternate scrubbing and soaking.

 

[geoffw]

I swear by this stuff, cleans apache barrels & various artillery pces too.

Bore Tech Eliminator Bore Cleaner

Bore Tech Eliminator™ Bore Cleaner is the patented, fast-acting, barrel safe, non-ammonia bore cleaner that has taken the

www.shootingsportsuk.co.uk

One liquid removes everything.

 

[Klenchblaize]

Keep scrubbing!

Waste of time if its imagined it will remove that Giant's Causeway-like pitting/cracking.

K

 

[C h r i s]

Is it cracking in the steel, or cracking in a carbon build up?

Pics in post 189 are looking better

 

[NP435]

Good luck sir! Much good advice posted and thanks for posting pics.

 

[zambezi]

Is it cracking in the steel, or cracking in a carbon build up?

Pics in post 189 are looking better

The pics are in sequence. Those in #189 are the furthest down the bore. The images in #188 defo show the Giant's Causeway erosion of the lands' shoulders. That is surely a projectile shredder

 

[Edinburgh Rifles]

i dont see what bullets you are shooting?
have you considered a lower friction/pressure bullet that rides on rings (in relief rather than old school driving band cuts of removed material)?

 

[A Guy Out West]

Don’t know what’s causing it but I do know how to get it clean. KG 12 is good but sometimes it just does not get it all out. You need Ballistol Solo Robla Mil copper remover. Follow the instructions and you will have it to bear metal in no time. If your worried about it’s strength, you can flush the barrel with a baking soda and water mix.

 

[zambezi]

i dont see what bullets you are shooting?
have you considered a lower friction/pressure bullet that rides on rings (in relief rather than old school driving band cuts of removed material)?

All my full bore centerfires throw Barnes tsx or ttsx. None of the others have any throat cracking.

Indeed, I have never heard of throat-cracking being attributed to projectile hardness. Throat land thinning - yes, cracking - no. Do you have a link to data that links cracking to projectile hardness?

My 6.5x55mm has not experienced any of the common reasons given for throat-cracking:

• over-pressure, over-temperature or combination thereof [unlikely given almost exclusive diet of Sako factory ammunition]
• rapid-fire usage [I am a deerstalker: Range time reflects cold bore conditions per field use]
• very high round count [ 600 rounds is not generally considered a high count]