cleaning barrel found this - ideas?

[jgrausa]

New 6mm, only 30 rounds down the tube. After cleaning, ran a bore scope and found this at the very end of the barrel. Not from cleaning as patches and nylon brush won't make those kind of marks. If I had to guess, they are remnants from the manufacturing process as a tool left the end of the barrel. I used a plastic pick to see if I could feel any grooves, but no "felt" scratch/groove, but you sure as heck can see it. Anyone see those marks before? Curious minds want to know. Thanks in advance for any input.
Joe

 

[papershredder]

Not quite sure, seems to be missing a little detail here

 

[MojoNixon]

New 6mm, only 30 rounds down the tube. After cleaning, ran a bore scope and found this at the very end of the barrel. Not from cleaning as patches and nylon brush won't make those kind of marks. If I had to guess, they are remnants from the manufacturing process as a tool left the end of the barrel. I used a plastic pick to see if I could feel any grooves, but no "felt" scratch/groove, but you sure as heck can see it. Anyone see those marks before? Curious minds want to know. Thanks in advance for any input.
Joe

Seems to be a picture missing. At least I’m not seeing one on my end.

 

[jgrausa]

Sorry guys, Had some difficulty loading pics. They are here now.

 

[hafejd30]

I’m no machines by any means but I’d guess it’s from some kind of indicator during the lathe setup. Clearly looks like the barrel was spun against a tool or similar based on the gouges in the rifling

How’s it shoot

 

[DairyDictator]

Looks like some bad tooling marks from a piloted crown tool.

Same questions as always for any borescope pic thread

Does it shoot?
If yes, move on and don't worry about it.

If no, contact the manufacturer for help. Nobody on the interwebs is going to be able to fix it for you.

 

[Charger442]

bore scope strikes again

 

[Haney]

bore scope strikes again

How do you think a bore scope could do that damage ? Oh I get it, you just had to comment because you don't agree with the use of bore scopes .

 

[Haney]

New 6mm, only 30 rounds down the tube. After cleaning, ran a bore scope and found this at the very end of the barrel. Not from cleaning as patches and nylon brush won't make those kind of marks. If I had to guess, they are remnants from the manufacturing process as a tool left the end of the barrel. I used a plastic pick to see if I could feel any grooves, but no "felt" scratch/groove, but you sure as heck can see it. Anyone see those marks before? Curious minds want to know. Thanks in advance for any input.
Joe

I have seen those marks before , factory barrels mostly . It's what you think it is .

 

[jgrausa]

How's it shoot? After dialing in my zero, I was .50 MOA which I thought was plenty good after only 1 box of factory 108 eld. Just surprised to see what appeared to be tooling marks. Makes sense that a factory barrel would not have the attention to detail that a custom barrel would receive. Get what you pay for I guess.

 

[hafejd30]

.5 moa isn't bad. See how it does at longer ranges. Definitely some gouges in the rifling that could effect your bullet jacket just before it exits the barrel

 

[Charger442]

.5 moa isn't bad. See how it does at longer ranges. Definitely some gouges in the rifling that could effect your bullet jacket just before it exits the barrel

factory barrel shooting .5 moa is terrific.

 

[Charger442]

How do you think a bore scope could do that damage ? Oh I get it, you just had to comment because you don't agree with the use of bore scopes .

he thanked me in advance for my input.

 

[ShtrRdy]

It sure looks like there is some metal missing on the edge of the lands. You'll need to shoot it some to see if it makes a difference.

 

[DairyDictator]

How's it shoot? After dialing in my zero, I was .50 MOA which I thought was plenty good after only 1 box of factory 108 eld. Just surprised to see what appeared to be tooling marks. Makes sense that a factory barrel would not have the attention to detail that a custom barrel would receive. Get what you pay for I guess.

It's amazing shitty a barrel can look but still hammer (not a reference to your barrel specifically, more of a general comment)

 

[cas6969]

Sorry OP, you're not allowed to be curious about what the source of the marks might be. The Hide won't allow it.

 

[Chris1972]

Did you specify if this is a factory barrel? I know there’s a reason on a custom barrel they recommend cutting an inch off each end.


…. Or, was it indicated then cut to length, then removed and replaced for some reason? Have threads cut on a finished barrel, etc.

Just making shit up here that makes sense in my head.

 

[Sum Ting Wong]

No indicator is going to make those marks.

 

[papershredder]

My theory: Tooling marks made by the button. Most likely caused by metal shavings piled up around the button. Then the bore was subsequently lapped which smoothed the marks down. Gently use a dental pick and I bet you can feel those scratches. Since accuracy is not affected, mostly a non-issue. If the lapping stage is part of the manufacturing process, I bet the manufacturers never even noticed the scratches. They just plug gaged the ends, air gaged the center of the bore, ran a pin down the bore to check for straightness, and then wrapped it up and shipped it out the door.

 

[ironpony52]

If I seen that on a part I machined I would say poor material. Is it a forged barrel ?? almost looks like bad forging, too cold to weld itself together.
Too random for me to say tool marks.

 

[jgrausa]

Did you specify if this is a factory barrel? I know there’s a reason on a custom barrel they recommend cutting an inch off each end.


…. Or, was it indicated then cut to length, then removed and replaced for some reason? Have threads cut on a finished barrel, etc.

Just making shit up here that makes sense in my head.

Yes, this is a factory barrel. You are right that if I cut an 1" off then end that alleviates any potential issue. I figure to shoot to about 60 rounds then start on some longer distances and see if I can maintain consistent tight groups. Then decide if I need to address the issue further.

 

[jgrausa]

My theory: Tooling marks made by the button. Most likely caused by metal shavings piled up around the button. Then the bore was subsequently lapped which smoothed the marks down. Gently use a dental pick and I bet you can feel those scratches. Since accuracy is not affected, mostly a non-issue. If the lapping stage is part of the manufacturing process, I bet the manufacturers never even noticed the scratches. They just plug gaged the ends, air gaged the center of the bore, ran a pin down the bore to check for straightness, and then wrapped it up and shipped it out the door.

From the manufacturer: "A carbide rifling button is drawn through the barrel to produce the rifling grooves at the appropriate twist rate for each caliber. This produces a groove diameter deviation of less than 2/10,000 (or .0002”) of an inch. It’s the same result that many gunsmiths accomplish by hand lapping."

 

[Shoots 700's]

People need to stop bitching about factory mass production barrels

 

[papershredder]

If I seen that on a part I machined I would say poor material. Is it a forged barrel ?? almost looks like bad forging, too cold to weld itself together.
Too random for me to say tool marks.

When I see marks like that on the parts I machine, I check my coolant lines and resharpen or replace the tool in question. FYI - 6mm is not a standard "COLD" hammer forged caliber. Lothar-Walther doesn't even offer a hammer forged barrel in that caliber. There's not a whole lot that could cause those marks. Maybe the drill for the bore went bad at the end of it's cut, got replaced and the new drill used to clean up the bore leaving some scratches behind, but that doesn't explain why the scratches are consistent in size between the lands and grooves. Another possibility involves the op got his cleaning rod stuck trying to reverse the stroke and had to hammer the rod out or chucked his cleaning rod in a drill. One last possibility is the bore was hand lapped and the person doing the lapping was careless in his process.

 

[papershredder]

From the manufacturer: "A carbide rifling button is drawn through the barrel to produce the rifling grooves at the appropriate twist rate for each caliber. This produces a groove diameter deviation of less than 2/10,000 (or .0002”) of an inch. It’s the same result that many gunsmiths accomplish by hand lapping."

Lol, the purpose of hand lapping is to smooth out tooling marks and improve the surface finish inside the bore. For my original theory that would mean the marks were made within the first couple passes of the button, then cleaned up some in the final passes. So, person making the barrel caught the issue, fixed the tooling issue, and then didn't thoroughly inspect the barrel afterwards, or he did but said fuck it and sent it anyway. I guess we can eliminate any issues with barrel lapping since they don't lap their barrels. Judging by the pics, maybe they should reconsider. A good finish is not what the buttoning process is known for.

 

[supercorndogs]

Inspected it? What factory rifle barrel gets borescoped for QC? None would be my guess.

 

[saddlerocker]

I have similar marks in a Hawk Hill barrel I got in November of last year.
Not as bad as yours. But similar looking, just inside the muzzle.
Are you spinning the borescope after entering through the muzzle?
My barrel is a 223, so there is not much wiggle room with the teslong, and I got it wedged on my first scoping, spinning it around to look all over. (I'm much better with it now, but do assume I caused damage).

Either I scratched my barrel with the borescope, or it was there from the gunsmith.
350rnds in and it is still there, not wearing down much.

The "How's it shoot" thing really doesn't matter.
I'm an amateur getting ~.8MOA with factory ammo, but could/should that barrel be doing .5MOA?

Attached some crappy snippets from a borescope video last week. This damage is right inside the muzzle.

 

[Jmccracken1214]

I have similar marks in a Hawk Hill barrel I got in November of last year.
Not as bad as yours. But similar looking, just inside the muzzle.
Are you spinning the borescope after entering through the muzzle?
My barrel is a 223, so there is not much wiggle room with the teslong, and I got it wedged on my first scoping, spinning it around to look all over. (I'm much better with it now, but do worry I caused damage).

Either I scratched my barrel with the borescope, or it was there from the gunsmith.
350rnds in and it is still there, not wearing down much.

The "How's it shoot" thing really doesn't matter.
I'm an amateur getting ~.8MOA, but could/should that barrel be doing .5MOA?

What the hell is your borescope made of???

You realize that a bullet is compressed, and digs into the rifling of the barrels as it fly's down it at 2800+ fps... with an explosion behind it...

But sliding a tiny aluminum cased camera in the barrel did this? No way.

 

[saddlerocker]

What the hell is your borescope made of???

You realize that a bullet is compressed, and digs into the rifling of the barrels as it fly's down it at 2800+ fps... with an explosion behind it...

But sliding a tiny aluminum cased camera in the barrel did this? No way.

Maybe not. I hope not. But I have read many times about borescopes causing damage. Same with cleaning rods that should be softer than barrel material.
Plus, I did get it wedged like an idiot when I first got it. (.223 bore is barely larger than the Teslong)
The photos from the OP had me question this though, as his marks look similar.
Im not sure what caused the marks in my barrel (there are a couple more mid-bore scratches across the rifling and grooves).
Could have been me, or not. I have since learned to be much more careful, but have not caused any NEW marks, which again makes me question whether I caused them at all.

 

[Rubicon Precision]

My money would be on long stringy chips got pushed into the bore on the machining op for the muzzle. It’s too inconsistent to be tool marks, and it marked up both the lands and grooves.

A factory rifle, I’d rate it a solid meh. I wouldn’t want to see that in a match barrel you paid good money for, likely waited a long time to get, and paid good money to get it chambered/crowned.

 

[Mordamer]

I've seen those exact marks before near the muzzle and I know exactly what caused the ones I saw. I parted off the end of a new barrel blank to thread the muzzle. The parting off left a nasty bur that interfered with my dial test indicator. I stuck a deburring tool in the end and gave it a few twists.
I left nasty scratches on the rifling by accident with the tip of the deburring tool that looked like the scratches in the picture. Not fun.

 

[Baron23]

I have similar marks in a Hawk Hill barrel I got in November of last year.
Not as bad as yours. But similar looking, just inside the muzzle.
Are you spinning the borescope after entering through the muzzle?
My barrel is a 223, so there is not much wiggle room with the teslong, and I got it wedged on my first scoping, spinning it around to look all over. (I'm much better with it now, but do assume I caused damage).

Either I scratched my barrel with the borescope, or it was there from the gunsmith.
350rnds in and it is still there, not wearing down much.

The "How's it shoot" thing really doesn't matter.
I'm an amateur getting ~.8MOA with factory ammo, but could/should that barrel be doing .5MOA?

Attached some crappy snippets from a borescope video last week. This damage is right inside the muzzle.

I am very skeptical that you could scratch steel with a Teslong mirror.

 

[Holliday]

bore scope strikes again

Fever-dreams strikes again…..

 

[tomme boy]

Maybe not. I hope not. But I have read many times about borescopes causing damage. Same with cleaning rods that should be softer than barrel material.
Plus, I did get it wedged like an idiot when I first got it. (.223 bore is barely larger than the Teslong)
The photos from the OP had me question this though, as his marks look similar.
Im not sure what caused the marks in my barrel (there are a couple more mid-bore scratches across the rifling and grooves).
Could have been me, or not. I have since learned to be much more careful, but have not caused any NEW marks, which again makes me question whether I caused them at all.

The reason the bore scope caused damage is because you looked at what was in your barrel and proceeded to destroy it by cleaning it with everything you could get your hands on.

Borescopes are good for 2 things. Checking your cleaning schedule. And looking in the barrel IF there already is a problem. Ignore what the inside looks like. If it shoots WHO CARES!!!!

I have mausers that looked like they were never cleaned after corrosive ammo. They literally look like a sewer pipe. One is so bad you can barely see the rifling. But you know what? I can hit a 24" steel plate every shot at 800 yards with it.

 

[saddlerocker]

The reason the bore scope caused damage is because you looked at what was in your barrel and proceeded to destroy it by cleaning it with everything you could get your hands on.

Borescopes are good for 2 things. Checking your cleaning schedule. And looking in the barrel IF there already is a problem. Ignore what the inside looks like. If it shoots WHO CARES!!!!

I have mausers that looked like they were never cleaned after corrosive ammo. They literally look like a sewer pipe. One is so bad you can barely see the rifling. But you know what? I can hit a 24" steel plate every shot at 800 yards with it.

Where did you get that idea from?
I got this barrel. Shot it twice and cleaned it normally before getting the borescope.
I never tried to "clean away" damage.

OP's pictures and the longer I continue to see no new marks in my barrel, the more I believe it was marred from machining.