Brass scratches or gouges

[Everdeeper43015]

Just got back from a range trip and was decapping my brass. I noticed scratches(feel it with fingernail depth) about 1/4 of an inch up from the head of the case. A quick inspection of my chamber reveled a groove that I could feel with a dental pick. It in no way is affecting the rifles performance and I don't think it is taking too much brass. My question is, where did this come from and what do I do to fix it? Info on the rifle: Rem 700, SPS with a 20" barrel. I bought the rifle second hand and am the third owner. I have put 300 rounds down range with it. No "hot" loads and have not noticed any difficulty on pulling or lifting the bolt. It is not an action screw or scope base screw. It is in the left hand side of the chamber. Thanka all and shoot straight!
Travis

 

[jdknotts1]

I'm quite interested to hear the answer myself.

The only thing I could think of is cleaning procedure. Maybe scratching the chamber with a steel cleaning rod without a guide?

 

[Everdeeper43015]

I use a guide, brass or nylon brushes and a coated rod. If I could take a picture of the "mark" I would, but it don't have that ability. I was almost wondering if it was from tooling. If it matters, the "mark" is running lengthways with the barrel.

 

[jdknotts1]

Sand or grit getting in the chamber while/before you're chambering a round? any chance you save your brass? If you do, look at some of them from that day and see if there are any gouges in the brass