rings between neck and shoulder??

[Ohlson7mm]

just got back from the range put all my now once fired brass in the tumbler and when it was done i noticed the small rings on the brass and its on all of the ones i shot.
this was all new lapua 7mm08 brass, brand new barrel, i loaded 50 with a light load to brake in the barrel , and i loaded a few for a pressure work up. barrel shot great all worked as it should have but ive never seen this before maybe machining marks in the chamber?? any thoughts
barrel is a 24" 1-9 savage pre fit carbon fiber i had ordered and i just rechecked my headspace twice all good there
hopefully u can see on my pictures

 

[MagnumManiac]

Looks like a bit of swarf got stuck in a flute and marked the chamber….no biggie, it will polish out with scotch brite if you're concerned by it.

I have a few chambers with similar marks, if they're not deep and pose no mechanical lock, all is good.

Cheers.

 

[Ohlson7mm]

got ya , I can barely feel them with my finger nail, id just never seen that before