I notice you are loading cast bullets. In the past I also had problems with inconsistent OAL on my loaded rounds. Make sure the bullet seating plug fits the nose profile of the bullet. If it doesn't fit it will mar the nose of the bullet. Lee can make you a bullet seating plug that will fit the bullet if needed. If it is a bullet from one of their molds they can send you a seating plug that will fit using the mold for reference. If you don't know the source of the bullet mold you will need to send them a sample bullet and they will make you a seating plug up using the bullet for reference. I have had them make several custom seating plugs to match bullets I use. They did a great job. Another issue I encountered was build up of bullet lube on the bullet seating plug when loading cast bullets. Before each loading session I remove the plug and clean all the build up off of the area that contacts the bullet.
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