What caused this? New photo

[RetiredArmy]

6.5 creedmoor, American whitetail 129 gr, factory ammo. Savage 10 fcp-sr, traded from a buddy. While cleaning rifle, used my Lyman bore scope to check on my cleaning. Started at chamber and found the strange markings on the chamber. Started looking at brass i fired yesterday and this is what I found on all 10 pieces of brass. The markings on the chamber a the mirror image of the brass. Any idea what caused them, and what should I do with it?
Thanks Bill

 

[WillyTP]

Just scratches in the chamber. You can take some 220 grit Emory cloth on a wooden dowel and twist it in the chamber to help clean it up.

 

[RetiredArmy]

The brass is "dented" when you run a thump mail over them. Almost like something was in the chamber when fired and is imbedded? (Into the chamber)
Thanks Bill

 

[WillyTP]

Then the Emory cloth should help clean that up. If you don’t have any do you have a large bronze barrel brush that’s just a little larger than the chamber diameter? If you do then clean the chamber real good with the brush followed by a bore mop should help you out.

 

[RetiredArmy]

Willy i don't have any emory cloth, but I do have brass brush and jb bore paste. I'm wondering if it could be brass bristles left in the chamber and fired on. The half box of ammo that I got with the rifle, all the empties had those dents in them.
Thanks Bill

 

[WillyTP]

If you got the rifle used then anything is possible. Give it a good old fashioned cleaning and see if that helps. Just don’t “polish” the chamber, it’ll make your brass stick in there then. And if it don’t clean up much don’t sweat it too much, one of the best shooting barrels I’ve had also made some of the ugliest brass you could imagine....

 

[Bill K]

What or where it came from, you may never know. Clean that chamber well, in doing so you probably will polish what it is out. Then when you fire a couple more rounds, you will see if it did clean out.

 

[carlsbad]

I don't recommend guessing what you are doing when modifying your chamber. --Jerry

 

[RetiredArmy]

I don't recommend guessing what you are doing when modifying your chamber. --Jerry

I agree 100%. Not going to modify anything, just trying to figure out what it might be. If it's something that has been "shot" into the wall of the chamber (brass bristles) how to now get them out. The reason I say brass bristles, is when looking at the chamber with a bore scope some of the lines are brass in color. Others are just lines in the stainless steel. I would up load the pictures from the bore scope of i were more computer literate!
Thanks Bill

 

[Twicepop]

I wouldn't use emery cloth in the chamber, it's too abrasive and may create additional problems. Crocus cloth has much finer surface grit and could polish out the chamber marks. If it was my gun I use chamber mop(s) with Clover compound followed by J-B then Fitz to polish out the marks.

 

[Uthink Uknow]

Those scratches don’t look as though they’ll hurt anything; just shoot it as is. Show it to some guys at deer rifle sight in days. I’m sure they’ll have theories.

 

[Ggmac]

Too many unknowns , it's a factory barrel so anything is possible. Shoot it and replace it when it's shot out . If you reload use good lube when full length sizing . Please keep us up dated if any problems arise with the reloading process.

 

[Nick Caprinolo]

If you can't remove it with a bronze brush, do not and I mean not use emery cloth or anything like it. A human hair is about .003 thick. What you have there is so minuscule that it defies measurement with anything in your tool box. Either forget it and enjoy your rifle or take it to a gunsmith for a valid opinion.

I had vertical scratches on the cases of one of my rifles and found the culprit was brass on my die. I used 220 grit compound on a breach mop to hone it out. Then polished it with 600 grit. Problem solved. I don't think I would do this in the breach of my rifle without consulting a gunsmith.

 

[Richard Coody]

View attachment 1114203
6.5 creedmoor, American whitetail 129 gr, factory ammo. Savage 10 fcp-sr, traded from a buddy. While cleaning rifle, used my Lyman bore scope to check on my cleaning. Started at chamber and found the strange markings on the chamber. Started looking at brass i fired yesterday and this is what I found on all 10 pieces of brass. The markings on the chamber a the mirror image of the brass. Any idea what caused them, and what should I do with it?
Thanks Bill

To me it looks like a burr in the chamber that scratches the brass on extraction. How new is the barrel? Usually they polish out after some use. Should be pretty easy to polish out with some losso or jb on a bore mop.

 

[RetiredArmy]

To me it looks like a burr in the chamber that scratches the brass on extraction. How new is the barrel? Usually they polish out after some use. Should be pretty easy to polish out with some losso or jb on a bore mop.

I'm not sure how old it is as I traded for it.
Thanks Bill

 

[RetiredArmy]

This is a screen shot of my chamber markings. Had to shrink photo to get to load. Sorry it is a little grainy. See the out line that caused mark's in brass

 

[varget204]

My guess would be from jamming cleaning rod jag,or brass brush,a lot of brushes have sharp edges on them where they are crimped.Have seen chambers scratched,necked,etc from improper cleaning,can also happen w/case head seperation extraction of case.Try a slotted jag with a Maroon colored piece of Blending material[looks simular to scotch brite,pad; but a lot finer,Most auto supply and Wal-marts sell them.Can also use the grey one{FINE}on a drill,the cheap 3 pc,brass .22 lr cleaning rod sections work good,use 1 or 2 sections,Soak it w/hoppes #9 or simular fluid,it will polish out marks,may take a little time,this process also works great for scratched reloading dies.If you use Emory or Crocus cloth you could remove too much,if not very carefull

 

[Ned Ludd]

No one in their right mind would ever try to polish imperfections out of a rifle chamber using 220 grit emery cloth.

 

[msinc]

First a disclaimer: I haven't been in my right mind since those two Mexican hookers beat me senseless....but here goes.
What I am seeing looks like it is going around the case/chamber. I have had similar marks on rifles and fired cases I chambered and it was a galled spot on the chamber wall caused by poor lube on the chambering reamer. I have had this happen several times and it always happened just as I was finishing up {of course, why in the hell wouldn't it???} so I had to set the barrel back and have another go at it.
Dave Manson suggested I try a lube called Viper Venom.....haven't had one gall since. Yours doesn't appear like it is too terrible. Does the bolt click on extraction??? If not I would just shoot it as it's not big or deep enough to really hurt anything and is a lot of work to fix it. Sometimes when it does this the galled spot is much deeper and wider. It can happen anywhere in the chamber, but for me it was mostly happening immediately below the junction of the shoulder and sidewall. Suggest a bore scope inspection of the chamber to confirm.

Edit: the only thing I know of that will safely polish a chamber is the hone tools made by Brush Research manufacturing. They are available in both 800 and 1200 grit and are a small "ball" type hone. They just polish and make extraction easier, they will not fix a galled spot or scratch.

 

[dcali]

I’d just shoot it as is. Factory barrels are what they are. To me, given what I see here, it looks cosmetic. Any effort put into fixing it is probably better used on a new higher quality barrel.