I seat my Gator checks in a hand die I made that holds the bullet aligned and seat them with an arbor press. I know that at least then, they are seated to the bullet base and square. I then run them into a sizing die, base first. When they come out, they aren't flat anymore, there is a dish in the check, and I have no assurance they didn't cock going into the sizing die, even though my rig has an ejector rod that is held at the top of the stroke that I press against. But for sure, they were flat when I seated them at first, then with the crimping/sizing, the dish forms, which means the edges may not seated firmly against the bullet base anymore.
Seems a method of holding the check against the bullet base WHILE sizing would not allow that dish to happen. Ideas?
Accuracy is the goal here, the base is important.