I was seating on the first MEC and it did pretty good but sometimes my runout would go above .003, last couple days been using the replacement, my highest runout has been .002 and only a few and been doing some brass I saved from cheap 223s, runout has hovered at .001 but I am getting many now around 0, needle is jiggling in place which could be slight imperfections in case, percentage wise I have never had this many so close to zero. Seating doesn't involve much pressure and I believe the easier you allow it to center itself the better, when you put case in holder you can set it more to the right or left or back and forth so anything you do to cut down on any resistance will allow it to center itself better. If a ram is sloppy it has a little bit of a tilt to it which would cause it not to be perfectly square to die and press harder on one side of the base than other, mind you very tiny but my theory with reloading is all the little things add up, I'm even still slightly dipping the base of bullet in hbn so it can slide easier on shell holder and have noticed an improvement in runout overall, not huge but enough that I keep doing it, my bullets runout wise have been improving every week so I feel I'm moving in the right direction.