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Barrel Pitting/Peening

DSPrecision

Private
Minuteman
Dec 28, 2021
40
22
Denver
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I’ve got a 6.5 Creedmoor barrel with about 1,200 rounds through it. Within the last 200 rounds, I’ve noticed what looks like peening on the edge of the lands in the first few inches of the barrel. I’ve also noticed what appears to be small circular pores or pits that have also recently developed. Any idea what could be causing this? It shoots well, but want to identify the cause regardless.
 

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What chemicals are you using to clean it? Ever used your bore scope to ensure the barrel is completly free of those chemicals after using them?
 
I think you are just seeing normal wear on the land edges. The little black spots could be metal pulled off the surface. Here is my barrel with 1670 rds through it showing a similar rough edge to the lands. Not the best picture. You are clean the barrel pretty aggressively with a bore paste?
WIN_20220227_14_51_27_Pro.jpg
 
What chemicals are you using to clean it? Ever used your bore scope to ensure the barrel is completly free of those chemicals after using them?
I’ve used CLR, Boretech, Tactical Advantage, Flitz Bore Polish, and Iosso. I clean every 50-100 rounds. I’m pretty good about running several dry patches down after cleaning so solvent isn’t sitting in there.
 
Sure. I would think that if I were over cleaning the entire barrel would look like that and the crown would be ruined. It’s only the first few inches that look this way.
You didn't lay out your entire procedure, but people who use abrasives are usually getting after the throat more than anything else. It looks to me like youre literally scrubbing the lands out of the throat, and you're doing it at a rate thats faster than the developement of fire cracking that should be there.



@Frank Green
 
You didn't lay out your entire procedure, but people who use abrasives are usually getting after the throat more than anything else. It looks to me like youre literally scrubbing the lands out of the throat, and you're doing it at a rate thats faster than the developement of fire cracking that should be there.



@Frank Green
That could explain the ‘peening’ on the edges of the lands, but what could be causing the round pits?
 





pick your poison and do what you will have fun either way .
 
That ain't doodly squat and agree that cleaning every 50 or so rounds is far more than I even contemplate.

I clean between 2-00-300 rounds, use Bore Tech (carbon remover followed by copper remover, generally), never use abrasives or CLR (ain't an old iron bathtub), and I absolutely don't care about the carbon in the fire cracking nor the slight wash of copper left in the grooves. Its nothing and getting it out would require more far abuse of the barrel that would outweigh any possible precision benefit I may garner.

This is right at 1,800 rounds in a Proof SS M24 chambered in 6.5 CM and about where your pic was taken...past the throat itself a few inches

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Thats craziness. Did you ask them if that includes abrasives? Im guessing it doesn't. With that short of an interval, a bartlein or krieger takes 3-4 short stroked wets to come out clean using a quality solvent.
 
Who recommends that cleaning interval? That is just crazy?
 
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Thats craziness. Did you ask them if that includes abrasives? Im guessing it doesn't. With that short of an interval, a bartlein or krieger takes 3-4 short stroked wets to come out clean using a quality solvent.
It probably does not include abrasives.
 

That’s just insane. When you get a new barrel please don’t do that again and lose most of those cleaning products. A good solvent and an oil are all that’s needed. I use Butch’s Bore Shine and then when done some Kroil to flush out and a few dry patches and done. No need for abrasives.
 
Speedy's mix of 2/3 Hoppe's Black powder solvent and 1/3 of Hoppe's #9. Is all you need to clean out the carbon and a little copper. Won't hurt the barrel to leave in overnight if you have too!
 
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-Don't be concerned about the appearance of the edges of your lands, they will break down from normal wear and use
-I don't think you need to clean as often as you are, but I also don't think it's harmful to the barrel
-if you were overcleaning, with a paste for example, your edges of the rifling would be more polished or rounded looking. I don't see that
-regarding your black specks, this is the unknown. Generally corrosion from chemicals will result in larger freckle shaped pits, or a snail trail of corrosion. That's not what I'm seeing here. Get your light right and see if there's a depression surrounding the black specks. Could be small voids in the steel- but Iwould also think that such voids would have collapsed by now and be more apparent. Even if it is corrosion or a void, it means nothing until it starts to create excessive or unusual fouling. Filling with copper or copper streaks down steam for example
 
-Don't be concerned about the appearance of the edges of your lands, they will break down from normal wear and use
-I don't think you need to clean as often as you are, but I also don't think it's harmful to the barrel
-if you were overcleaning, with a paste for example, your edges of the rifling would be more polished or rounded looking. I don't see that
-regarding your black specks, this is the unknown. Generally corrosion from chemicals will result in larger freckle shaped pits, or a snail trail of corrosion. That's not what I'm seeing here. Get your light right and see if there's a depression surrounding the black specks. Could be small voids in the steel- but Iwould also think that such voids would have collapsed by now and be more apparent. Even if it is corrosion or a void, it means nothing until it starts to create excessive or unusual fouling. Filling with copper or copper streaks down steam for example
The black specs in the barrel appear to be slightly depressed around the edges. The black spots in the neck and shoulder look more like small hollowed out spots without having the surrounding material 'pressed' in. Curious to hear more of your thoughts.
 
On the subject of cleaning frequency... I've seen hundreds of barrels that were cleaned every 5-25 rounds for their entire life. Bronze brushes (pulled back through the crown even) and BoreTech Eliminator with some Wipeout mixed in, and very rarely but sometimes Iosso if they started acting up.

Match-level accuracy out of those barrels was almost exactly in line with the typical "rules of thumb" you see here. I.e. a 6.5 Creedmoor lasted 2500-3000 rounds before dropping off. Every so often they were tested and re-tested with reference bullets to ensure they were still up to snuff.

Cleaning done properly won't hurt anything. Don't slam the rod into the lands, don't put abrasives on a brush, etc...

In certain cartridges (6.5 SAUM, 6.5 PRC), a cleaning every 50-150 rounds is necessary, IMO. In others (.222, .223, 6 ARC, 6.5 Grendel), you can probably get away with a lifetime without cleaning.
 
I’ve used CLR, Boretech, Tactical Advantage, Flitz Bore Polish, and Iosso. I clean every 50-100 rounds. I’m pretty good about running several dry patches down after cleaning so solvent isn’t sitting in there.
I did a test several months ago on CLR. You leave it in long enough it will pit/corrode the barrel. Even SS barrels. CM it effected really fast.

DON'T and I mean DON'T use a brush with an abrasive cleaner. It will wreck/damage the bore. No way around it. I've commented on this more than I even care to say anymore. Not just from damaging the lands but it will change/effect bore and groove sizes as well.

The lands on the edges especially back at just in front of the chamber area will take/show the wear the soonest. That being said though what I see in your pictures doesn't look normal.

First question you have to ask yourself is: Does the gun shoot good accuracy wise and will it hold accuracy for X amount of rounds on it? If the accuracy is good etc...stop looking in the dam barrel and shoot just shoot it and clean it. Maintain it though.

Also if you've been putting the gun away dirty for extended periods of time....even the ss barrels will pit/corrode. It's not a question if they will or not. The answer is yes they will and again it's just a matter of time. The powder fouling and copper fouling in the bore will react with the mositure/humidity in the air. Then the pitting starts.

If the bore of the barrel gets damaged this is just another reason that causes bullet failures as well.

Yes we've seen SS tumbling pins get left in cases when reloading....you should see what kind of damage that does to the bore of the barrel when the round gets fired.

Later, Frank
Bartlein Barrels
 
I did a test several months ago on CLR. You leave it in long enough it will pit/corrode the barrel. Even SS barrels. CM it effected really fast.

DON'T and I mean DON'T use a brush with an abrasive cleaner. It will wreck/damage the bore. No way around it. I've commented on this more than I even care to say anymore. Not just from damaging the lands but it will change/effect bore and groove sizes as well.

The lands on the edges especially back at just in front of the chamber area will take/show the wear the soonest. That being said though what I see in your pictures doesn't look normal.

First question you have to ask yourself is: Does the gun shoot good accuracy wise and will it hold accuracy for X amount of rounds on it? If the accuracy is good etc...stop looking in the dam barrel and shoot just shoot it and clean it. Maintain it though.

Also if you've been putting the gun away dirty for extended periods of time....even the ss barrels will pit/corrode. It's not a question if they will or not. The answer is yes they will and again it's just a matter of time. The powder fouling and copper fouling in the bore will react with the mositure/humidity in the air. Then the pitting starts.

If the bore of the barrel gets damaged this is just another reason that causes bullet failures as well.

Yes we've seen SS tumbling pins get left in cases when reloading....you should see what kind of damage that does to the bore of the barrel when the round gets fired.

Later, Frank
Bartlein Barrels
Frank I know you don't have time for this but I have one question to clarify your point on abrasives.

Are you saying to not use abrasives on a brush or really, not to use abrasives at all. It doesn't seem to me that the abrasive on the brush alone would be much worse than the abrasive on a patch wrapped around a brush.

Getting the hard carbon out of the tight corners of the lands is where I can see the abrasives on a brush only being useful. We really need some type of chemical cleaner that is able to remove the hard carbon. I have heard about all the top end cleaners and such but there is no real proof that any of these work really well. With everyone running a borescope these days you would think this could be worked out and proven.
 
Frank I know you don't have time for this but I have one question to clarify your point on abrasives.

Are you saying to not use abrasives on a brush or really, not to use abrasives at all. It doesn't seem to me that the abrasive on the brush alone would be much worse than the abrasive on a patch wrapped around a brush.

Getting the hard carbon out of the tight corners of the lands is where I can see the abrasives on a brush only being useful. We really need some type of chemical cleaner that is able to remove the hard carbon. I have heard about all the top end cleaners and such but there is no real proof that any of these work really well. With everyone running a borescope these days you would think this could be worked out and proven.
Time? Time is in short supply bud! I'll help when and where I can.

In response to your question....any abrasive period and you use a brush with it....you are going to damage the barrel. My favorite pic is attached. The lands stick up and take the brunt of the beating. Also the guy polished a full .002" out of the bore and a .0015" out of the grooves. Search the forums you will find in depth discussion about this.

I've seen this damage with KG2 Borepast, Iosso, Witch's brew etc...again any abrasive cleaner with a brush at the same time = Damage.

Also how aggressive a guy is factors in. I've seen guys cleaning they're barrels like they are working on a clogged kitchen sink! I should probably say a plugged up toilet! LOL!

I do believe there does come a point in time that you do have to resort to something. I prefer either JB borecompound (blue label) and not the borebrite (red label) or using Remington 40x cleaner. Years ago that use to be called Gold Medallion before Remmy bought them out. Patch only and use the JB borecompond or the 40x cleaner. After I clean the bore with solvent and get it as clean as I can...I will follow up with a patch with JB or 40x. I'll full stroke the bore 10x and short stroke the throat area several more times with the same patch. I might do this depending on caliber after every 300ish or so rounds. Especially after the barrel has a lot of rounds on it and or after I clean the barrel with Sweets 7.62 solvent as I feel it works better (the JB or 40x cleaner) on the carbon build up. After I dry patch it out I follow up with a light coat of Hoppes and just dry patch the Hoppes out the next morning before I start shooting again. This is where the gun is getting 60 or more rounds on it in a single day during big matches. The throat area will build up with carbon the worse and it will be in like the first 6" to 8" of barrel length. This is caliber dependent. A 308win. barrel won't build up as fast or as much as a 300WM or a 300 Norma barrel will. Same if you stay with a 308 case capacity and turn it into a 243win. type chamber. Same case capacity but by reducing the bore size you have now turned it into a magnum round!

Picture attached is a accuracy test barrel I got back from Sierra after it would no longer hold .5moa or better. 308win. chamber. Other than running a dry patch down the bore before I had the barrel wire edm cut in half the is as I received it from Sierra and they have a strict cleaning procedure and number of rounds they fire in between cleanings that they follow. Look at the first say 6" of the bore from chamber towards the muzzle. See how black it is....that's the carbon you are seeing. Yes that's not a engraving typo. That barrel got 14,560 rounds on it and up to that point was still holding .5moa or better.

I've seen guys wreck barrels in as little as a 100 rounds with using an abrasive and a brush at the same time. Took out a full .001" out of the bore of the barrel. Rifling damage to the lands was already starting to show like in the first pic. One guy I replaced three barrels in the course of 6 months. I got fed up. I told him unless you change your cleaning procedure as you are wrecking the barrels. I'm done. I'm not replacing another one. I helped him the best I could! A few months later then he was complaining to a bullet maker they're bullets where bad and where blowing up. I'll guarantee it was damage to the bore from poor cleaning technique and not a bullet fault. A bullet that hits rifling like in the attached pic....plan on it coming a part!

Later, Frank
 

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I might do this depending on caliber after every 300ish or so rounds.
You use abrasive paste every 300 rounds? Wow, that's sort of my interval for normal cleaning 200-300 rounds which is just BoreTech Carbon Remover followed by their copper remover.

Thanks as always, Frank. As with many other topics, shooting related or not, there is a very wide range of differing opinions offered so one just needs to pick one "expert" source and stick with it. For barrels, its you...after all, I shoot your barrels so why would I listen to anyone else?

Cheers
 
You use abrasive paste every 300 rounds? Wow, that's sort of my interval for normal cleaning 200-300 rounds which is just BoreTech Carbon Remover followed by their copper remover.

Thanks as always, Frank. As with many other topics, shooting related or not, there is a very wide range of differing opinions offered so one just needs to pick one "expert" source and stick with it. For barrels, its you...after all, I shoot your barrels so why would I listen to anyone else?

Cheers
Your welcome!

Not all the time but it's a good average number.

Again regardless of round count if I use Sweets to clean because I'm in a hurry...after I dry patch that out I follow up with 40x cleaner. To me that will neutralize the possibility of any Sweets left over and get it out and works better on the hard carbon deposits. Then after I dry that out a light coat of Hoppes.

Again though no brush when I use that stuff.

If I'm not in a hurry just Hoppe's #9 solvent. Nothing else.

"Wow, that's sort of my interval for normal cleaning 200-300 rounds" from your reply above. You can get away with that with some calibers and when the bore is newer but as the bore wears fouling will go up and it might not hold accuracy for that amount of rounds being fired. I for sure won't do that with a 6.5PRC or a 300wm or a 338 Lapua etc...

Also think about this....you let the barrel get too fouled....and you create a problem from letting it get away from you....trying to fix it (do a real good cleaning) becomes even harder.

Goes back to my old saying...."know your gun. Pay attention to it! It will tell you what is going on...you just have to learn how to read it!"
 
Your welcome!

Not all the time but it's a good average number.

Again regardless of round count if I use Sweets to clean because I'm in a hurry...after I dry patch that out I follow up with 40x cleaner. To me that will neutralize the possibility of any Sweets left over and get it out and works better on the hard carbon deposits. Then after I dry that out a light coat of Hoppes.

Again though no brush when I use that stuff.

If I'm not in a hurry just Hoppe's #9 solvent. Nothing else.

"Wow, that's sort of my interval for normal cleaning 200-300 rounds" from your reply above. You can get away with that with some calibers and when the bore is newer but as the bore wears fouling will go up and it might not hold accuracy for that amount of rounds being fired. I for sure won't do that with a 6.5PRC or a 300wm or a 338 Lapua etc...

Also think about this....you let the barrel get too fouled....and you create a problem from letting it get away from you....trying to fix it (do a real good cleaning) becomes even harder.

Goes back to my old saying...."know your gun. Pay attention to it! It will tell you what is going on...you just have to learn how to read it!"
Thanks Frank!!

I have a Proof SS M24 in 6.5 CM with 2k rounds on it. I just ordered some 40X to give it a try.

Question, would use of a bore mop be good to apply the 40X. Seems like it would make greater contact than just a patch but....I'm open to input, of course.

Oh, and I know you posted that you are so busy that you can't spend as much time here answering questions so if this is a bother, just ignore.

Cheers
 
Thanks Frank!!

I have a Proof SS M24 in 6.5 CM with 2k rounds on it. I just ordered some 40X to give it a try.

Question, would use of a bore mop be good to apply the 40X. Seems like it would make greater contact than just a patch but....I'm open to input, of course.

Oh, and I know you posted that you are so busy that you can't spend as much time here answering questions so if this is a bother, just ignore.

Cheers
once on a subject...hard to turn off.

I don't use a mop.

I use a parker hale jag. Good cotton/flannel patches. Roll the patch around the jag like you roll a cigarette. Give the patch a twist with your fingers and it will to an extent keep it in place for you to start it into your bore guide. With a bore guide with a solvent port...ad your liquid of choice and good to go. Little harder with JB bore compound but not the end of the world. Using this jag does a couple of things in my opinion vs poking/spearing the patch. It gives you more surface area for the patch to do it's job.....and by rolling the patch it will help keep the tip of your cleaning rod centered as it goes down the bore. So even less of a chance of rod drag in the barrel in conjunction with a bore rod guide back in the receiver and. When you poke/spear the patch the patch doesn't fold evenly when you push it into the bore. Just the way I do it.

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@Frank Green When you say "Brush" are you talking NYLON brush as well ?
I normally use a NYLON brush soaked in Sweets 7.62 , then dry patch out ... then patch with Tetra to remove any Sweets residue. Then leave a film of Tetra in bore for storage...remove Tetra with a dry patch before a shooting session..
 
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There are no problems with bronze brushes if you're not a gorilla. I've seen an accuracy barrel similar to what Frank described above-- a .222 that made it 18,600ish rounds before it sluffed off. It had been cleaned every 5-25 rounds with a bronze brush its entire life.
 
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On a semi-related note, what patches are recommended? I see multiple sizes available, and I am shooting calibers between .22 and 308. Also, what material is recommended?
 
@Frank Green When you say "Brush" are you talking NYLON brush as well ?
I normally use a NYLON brush soaked in Sweets 7.62 , then dry patch out ... then patch with Tetra to remove any Sweets residue. Then leave a film of Tetra in bore for storage...remove Tetra with a dry patch before a shooting session..
I'll use a brush when I feel the need to.

Nylon or bronze....just never with an abrasive cleaner. That's the no no!

Never use a stainless steel brush in a barrel!
 
On a semi-related note, what patches are recommended? I see multiple sizes available, and I am shooting calibers between .22 and 308. Also, what material is recommended?
If your using a Parker Hale jag....for the 30cal I use 2.25" square patches.

For a 6.5mm I use 1.75" square patches (I just use a scissors and cut to size).

22cal etc....the patch should be fully long enough to cover the diamond/barb area of the jag up to/just before the end where the jag goes rod diameter. The patch cannot extend on to the major diameter at the end or you will be trying to jam the rod into the bore.

Patch should be snug enough but not too tight that the rod is bending or flexing or if you hear the patch squealing going down the bore (especially the first patch down a dry bore)....if either of these are happening the patch is too tight. The dirt/debris in the bore has no where to go but get forced/jammed between the patch and the bore. The hard carbon particles can scratch the bore as well.
 
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On a semi-related note, what patches are recommended? I see multiple sizes available, and I am shooting calibers between .22 and 308. Also, what material is recommended?
Good cotton/flannel patches. If you have to buy the patches I like the pro shot patches. Think they make a std. 2.25" square which works perfect for 30cal.

We buy bulk material here....and we cut all the patches out of bulk material. It's cheaper cost wise that way vs buying finished cut patches and the amount of patches we go thru here! Like a broken water faucet!

We should buy stock in the fabric maker/supplier!
 
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Your welcome!

Not all the time but it's a good average number.

Again regardless of round count if I use Sweets to clean because I'm in a hurry...after I dry patch that out I follow up with 40x cleaner. To me that will neutralize the possibility of any Sweets left over and get it out and works better on the hard carbon deposits. Then after I dry that out a light coat of Hoppes.

Again though no brush when I use that stuff.

If I'm not in a hurry just Hoppe's #9 solvent. Nothing else.

"Wow, that's sort of my interval for normal cleaning 200-300 rounds" from your reply above. You can get away with that with some calibers and when the bore is newer but as the bore wears fouling will go up and it might not hold accuracy for that amount of rounds being fired. I for sure won't do that with a 6.5PRC or a 300wm or a 338 Lapua etc...

Also think about this....you let the barrel get too fouled....and you create a problem from letting it get away from you....trying to fix it (do a real good cleaning) becomes even harder.

Goes back to my old saying...."know your gun. Pay attention to it! It will tell you what is going on...you just have to learn how to read it!"
Great information for all us barrel burners. I hear the concern of removing the residue of those harmful cleaners on our barrels. When I use those chemicals, I will run a patch with 70+ proof rubbing alcohol through the bore a few times. The alcohol will neutralize and wash out the cleaning chemicals. It’s not harsh on the bore. Run a dry patch afterwards through the bore. You can then treat the bore with your favorite lube. I also found that punching the bore with the alcohol increased the likelihood my cold bore shot would be part of the follow up shots group. Where I worked the cold bore shot was critical, to say the least. It also goes with Frank’s comment about knowing your rifle.
 
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