Took the new Kimber to the range today and put 29 rounds through it (would've shot the whole 100 round WWB value box had I not left it on the kitchen counter when I was loading the truck...) and when I picked up my brass I noticed that nearly all of them had a parabola shaped discoloration on one side (centered on the dent/scratch from the extractor). It would seem to me that the pattern shown is caused by hot gasses escaping around the casing. Is this normal, or something to worry about?

Nothing to worry about.  Probably from a rather light load failing to fully expand the case, resulting in an imperfect seal to the chamber wall, and allowing blow-by.

Normal nothing to worry about.

Your guess is correct the brass is not expanding enough to seal the chamber. Hotter loads show less of a ring.

cool. thanks guys. Guess I'm just being a "paranoid first time parent".

no biggie....very normal......

No biggie.. but just in case, you might want to change out your recoil spring...

OOPS.. Just saw where you said... "New" kimber... never mind...  

Interesting that they are ALL centered over the extractor claw mark. Possibly the chamber might be a bit out of round, a bit big, [oversize] or it is unlocking a bit early. While I DO see it occasionally, I usually don't see  it as pronounced as that in the same exact area. WWB is not really downloaded at all, and isa pretty close to spec so the brass possibly might be a bit hard also.

My biggest concern it that it will, after a long shooting session start to build up carbon and cause problems with the fresh round going into the chamber.