possible headspace issue?

[CINDERS]

I have the same appearances nothing to be overly worried about unless they are hard to extract you may want to polish the chamber very lightly with Iosso paste and I mean lightly as if it is too smooth some suggest the brass will not grip the chamber walls as good and increase bolt back thrust well that is what I have heard. I have snapped a couple or rounds fired from one of my 303's showing the same bulge the first one is on its 5th reload the last case is the one you have to watch out for and this is suffering a partial head separation (bin job, usually they are gone at about 10-12 reloads per case in my rifles). Looks as though you are getting a good seal around the case neck.

You can check your cases by putting a small leg 90 degree bend on a piece of thin wire and sharpen a point onto the tip have it long enough to reach to the bottom of the case place the tip against the side wall and slowly scrape upwards along the wall if you feel a slight indent then this is a sure sign it is on its way (see 2nd pic for approx location).
Others will come along shortly to also assist my advice is based what I have seen on this site and 30 years of reloading and shooting 303's