I know I'm late in on the thread, but I have gotten tired of trying to get consistent lengths with the Redding Competition die. It might be dead on when measured with a bullet comparator, but if your ogives aren't all identical, your lengths will vary. I see length spreads up to 0.020". I now seat everything once with a known setting that is longer than desired and then go back and measure each round, adjust the die accordingly and re-seat to get within +/- 0.003". This method works well, but it's very labor intensive.
I understand the issue with run-out, but a 0.020 difference in 9mm can lead to large pressure differences and large ES values. By the way, I'm using Zero 147 GN JHP-O bullets. Maybe there's an issue with different bullets coming off of different machines with different profiles.
Anyway, I may have to go back to the dillon seating die. Granted, adjustments are a pain, but the lengths are very consistent.
Chuck