It's never going to be absolutely straight along the length of the case. A visible bulge like that is a very good sign because it means you have good neck tension holding that bullet firm. No way is it going to set back while chambering and possibly cause harm to yourself and those around you.
The case is resized in your resized/decapping die to be smaller than the bullet. If it weren't, nothing would hold the bullet and you'd have an extremely dangerous load. When you insert a bullet larger than the case with the seating die, you will get some bulge - particularly where the case begins to thicken near where the bullet base is. It's perfectly normal, acceptable, and even desirable as long as it easily chambers.
I use .358" lead bullets in my 9mm, and mine are more visibly bulged than yours are in the pic. They work great
