Since I have started reloading for this .308 Winchester bolt gun I have been noticing two consistent scratches in the cases. This is becoming more pronounced due tighter tolerances of the reloaded cases versus factory. Now that is am looking for it I can see very light scratches on the factory cases after firing. So this has been there since new.
I am noticing that the scratches on the sized brass are more pronounced. If I lock and unlock bolt it gets progressively harder to open the bolt and I assume that is because particles of brass are getting between case and chamber as the burr scratches the brass.

How would I address this?
Chamber reamer to knock off the burr?
Modify a case with a rod that allows me to “lap” the chamber in that specific area with some compound?

The two scratches are approx 150 degrees apart. And yes the picts are correct. They go in two different directions. I don’t know why.:confised2:
See picts.

I'd suggest getting a good look with a bore scope to determine what you are dealing with.

I use my bore scope but not the clearest picts.

My first thought was possibly magazine feed lips scraping the case as it's being stripped from the magazine. That is if your rifle has a detachable box magazine. I had some Accurate mags that I had to polish the feed lips with some emory cloth to keep them from scratching up my brass. If it's a chamber issue, I WOULD NOT attempt to correct that myself without the proper tools and knowledge/experience. Thousandths of an inch might as well be miles when you're talking about firearms. Especially chambers. If it's not a magazine issue that can be identified and corrected, I would take it to a reputable gunsmith and go from there. He can bore-scope the chamber, identify the issue, and go from there.

The mag is plastic. The picts are of hand fed cases. It shows up in all cases. Even steel cases.

how's it shoot?

If it's a new rifle, send it back to manufacturer

if Old, take it to the 1911 Academy on HWY380, near Prosper. They should be able to diagnose your issue and take steps to fix it.

Seems to be something there in your pics that is a different color than the chamber. Do you have access to a side looking (90 deg) bore scope? Mine is a Lyman (not the best) but might give you a better look. You can bring it by sometime and give it a look if you like. The guys at S&S in Denton likely will have a good bore scope and could provide expert advice.

I know what I would do, but I'm not going to tell you to do it.

Stick wrapped in sandpaper??

Piece of brass, drill out the primer pocket, and tap it 1/4-20. Then I'd make a shaft long enough to reach out the back of the action, plus a couple of inches, with male 1/4-20 threads on one end. Little dab of valve grinding compound on the shoulder of the brass. Shaft chucked in the drill.

This is exactly what I was thinking about. I have a scope ring lapping kit with 220 grit compound.
Just place the compound on the case where the burr is or maybe place the compound in the chamber where the burrs are so the compound is not spread down the case.

If you had a choice between a brass or a steel case.... which would you choose.

Unless someone thinks a reamer Is a better option.

If the gun was from a smith that chambered it I would get them to fix it, if an off the shelf rifle,

JG and Pegasaurus ideas will work, reamer could be a good option but could have it cleared before you could pay to rent a reamer, and get it.

I would try the compound on a brass case first. If the case needs to yeild, it can.

Inspect after the brass attempt. If the burs are still there, go to a steel case.

Problem solved. Ended up using steel wool on a mop with a little compound.

That’s a clean chamber

Good deal!

Would you mind taking some measurements of brass that was fired before cleaning the chamber, as well as brass after cleaning the chamber?

Curios if there's even the slightest difference in case head to shoulder, diameter of the body, and diameter at the datum line. I doubt you removed even a thousandth of steel. That's probably impossible with the tools you just used.

I certainly plan on doing that and will share the results.

those before and after pictures are really different
same camera?

does look good now.

thanks for sharing

Glad you got it figured out. Looks great.

Good job !

Question...do you think it was a bur? or was it just a really dirty chamber?

I don't think you did based upon the pictures...but for others, be careful polishing on a chamber...you can get it slick enough it causes extraction issues.

Based upon my "condition" I was warned pretty early on in my lathe experiment that I did not want nice and polished chambers they do need some grit to them.

I had a similar issue a few years ago, I went with a Flex-Hone from Midway. FIxed it right up, good on you for figuring out a diy alternative!

Definitely a burr. Looking back at my fired cases since I bough the gun ,new, the scratches have been there since day 1.
I can still see same, but now very light, scratches on the chambered cases.
Before I did this, if I repeatedly opened and closed the bolt on a case you could feel the scratches with your fingernail.

As we expected... Other than the typical 0.xxx5 fluctuation on the digital calipers depending on thumb pressure. No measurable difference that can be detected with a digital caliper, between before and after. No apparent marks on any cases. No blow back of gases on the cases past the neck. No impact to accuracy either. Bolt function was smoother chambering the rounds and consistent tension when closing the bolt.
Mark’s on cases has been reduced by 85-90%. The scratches I was concerned about are still there when looking at them very closely but they are very light.
Can’t feel the scratches with my fingernail anymore. Similar or less than depth of typical chambering and extraction marks.