Don't know whether you saw this video or not regarding the Lee Safety Prime-does a pretty good job of explaing the installation, etc:
http://www.youtube.com/watch?v=3iVdU...eature=related
One other tip: the primer cup can be raised up or down by screwing it in or out. So if the Safety Prime is too close to the cup and is binding just screw the cup in to lower it.