I run it through the sizing die. I have seen a few out of round cases and it doesn't hurt doing it. I am working on a progressive press so it doesn't bother me to size it because the upstroke primes the case. I can see if you are using a single stage press you may want to skip sizing the case but I like to size my rifle brass when new on my single stage. I wouldn't worry about pistol brass I guess but like I said, I size because of the progressive.