Death of a 7MM Barrel (re-posted from elsewhere)

[Jay Christopherson]

I ran across this article, re-posted by Speedy on his Facebook site. It validates a lot of things that I've thought for a while regarding brushing, using bore pastes, and in general, over-cleaning a barrel. You can argue with their method (and undoubtedly, people will), but they took excellent images and were able to replicate their issue on demand, which is usually the first step in solving a problem. I had similar issues a while ago with a .260 barrel that was initially exceptionally accurate, and then fell apart at around 600 rounds. I was *extremely* aggressive about keeping it cleaned. Brushes, pastes, the works...

http://www.7mm.com.au/death-barrel/

Now, FWIW, I don't brush. I don't use bore pastes. I don't use a borescope, except to investigate a possible issue. I let the rifle tell me how things are working. It works for me, but probably isn't for everybody.

This is probably more applicable to guys shooting F-Class, sling, etc... short-range BR and maybe other BR disciplines have different requirements for accuracy and expectations of barrel life, from what I understand.

 

[Jay Christopherson]

It's probably worth noting that the person who conducted the test feels the issue has more to do with the use of brushing/abrasive pastes while the cleaning rod fails to spin with the rifling (thus wearing a groove in the barrel) and intends to keep using brushes and pastes as normal - although with a careful eye out for the rod following the rifling properly.

http://ozfclass.com/phpBB2/viewtopic.php?t=5898&postdays=0&postorder=asc&start=120

 

[jonbearman]

Something else has to be going on to just destroy the lands and no the grooves.They are both surfaces that are influenced by cleaning but I doubt it is JB doing the damage.It looks more like a stainless brush was used by accident or on purpose and then changed to bronze after they found out that stainless will damage a bore. I don't buy it that it was just brusing with a non spinning rod that rutted that barrel that bad.The scratches are all going in different directions instead of scatches all going the same way.

 

[Jay Christopherson]

Something else has to be going on to just destroy the lands and no the grooves.They are both surfaces that are influenced by cleaning but I doubt it is JB doing the damage.It looks more like a stainless brush was used by accident or on purpose and then changed to bronze after they found out that stainless will damage a bore. I don't buy it that it was just brusing with a non spinning rod that rutted that barrel that bad.The scratches are all going in different directions instead of scatches all going the same way.

What about the fact that the article writers were able to replicate the damage using just a bronze brush and bore paste? Granted, it took 800 strokes to do it, but still... unless they are completely fabricating their results which I don't believe would be the case.

They also stated that there was some some level of minimal damage in the grooves. Which I think actually supports the brushing/paste theory, especially if the rod is not turn with the rifling, since the lion's share of the damage would be occurring on the lands at that point.

 

[jonbearman]

The can states to use a tight fitting patch,at least mine does and you patch it instead of using a brush. I think this test is bogus,I have as well as others have used JB,Iosso<etc to clean with for years and years and my friends borscope shows nothing even remotely like this,in fact the bore looks perfect on the guns I ues it in. I don't use it in match barrels except for a carbon ring or an area of stubborn copper streak.

 

[Jay Christopherson]

Fair enough, although the point to this article was to demonstrate the case where someone uses a bronze brush with abrasive paste and doesn't pay attention to the cleaning rod spinning to follow the rifling. Heck, I was guilty of exactly that myself at one point. Granted, a specific case, but I know plenty of guys that do it that way, whether or not the can recommends it that way. I doubt this case would apply to someone who uses just a patch like you mention.

 

[6BRinNZ]

The can states to use a tight fitting patch,at least mine does and you patch it instead of using a brush. I think this test is bogus,I have as well as others have used JB,Iosso<etc to clean with for years and years and my friends borscope shows nothing even remotely like this,in fact the bore looks perfect on the guns I ues it in. I don't use it in match barrels except for a carbon ring or an area of stubborn copper streak.

The upshot for me is awareness. I clean the way I do because it works and don't care what others do. It would be worth having a look at the ozfclass thread as on the whole it is interesting and ultimately while difficult to absolutely prove it does go through a logical process of elimination....the barrel manufacturer got heavily involved...kudos to them for giving a rats even though it looks very much like user induced.

Cleaning techniques will continue to be argued about looong after we are gone

 

[Jay Christopherson]

The can states to use a tight fitting patch,at least mine does and you patch it instead of using a brush. I think this test is bogus,I have as well as others have used JB,Iosso<etc to clean with for years and years and my friends borscope shows nothing even remotely like this,in fact the bore looks perfect on the guns I ues it in. I don't use it in match barrels except for a carbon ring or an area of stubborn copper streak.

The upshot for me is awareness. I clean the way I do because it works and don't care what others do. It would be worth having a look at the ozfclass thread as on the whole it is interesting and ultimately while difficult to absolutely prove it does go through a logical process of elimination....the barrel manufacturer got heavily involved...kudos to them for giving a rats even though it looks very much like user induced.

Cleaning techniques will continue to be argued about looong after we are gone

+1, the threads are a worthwhile read and Bartlein added some good info after examining the barrel section he sent them.

 

[bsumoba]

I used to be religious about cleaning my barrel after every range session. I was using a brass brush and hoppes. I was then talking to Jeff Tierney and he mentioned to me that he does minimal cleaning. I then read his thing on AccurateShooter about barrel cleaning and decided to adopt his method. Since then, I have about 300 rounds down the tube and my barrel is hammering. Not a single patch, solvent, or cleaning rod in the barrel. I am a believer.

With the new powders, there is no real risk of corrosion so leaving the fouling in there will not affect the barrel, or at least, that is my opinion.

That said, here's another good video on barrels, break in and the likes:

https://www.youtube.com/watch?v=rW6SF-jlbkg&feature=youtu.be&app=desktop