I don't think I'm bumping the bullet between the seating and crimping process. I guess I could try to cleaning up the stem and see if anything improves.
I've been reloading for about a year now. Maybe being relatively new has me a little bit on edge with the tolerances. I try to work up a load and when I find what works best I try to replicate that is exact as I can with the equipment I have. 9mm is the only thing I load gives me problems like this.
I haven't seen any lopsided bulging. I flare the case mouth to the minimum, set the bullet on the case to get it as straight as possible and rotate 2-3 times before the bullet is fully seated. Sometimes I will randomly take 4-5 completed rounds and roll them on a smooth flat table just to see if any of them look like they were seated crooked.
Maybe the question I should be asking is what amount of OAL difference should be considered acceptable?