Wogpotter, that's correct - the bullet seating is being done in a whackamole. For the cases that have already been fired in THIS rifle, all the rest is being done in the whackamole also.
To my embarrassment, I managed to throw a squib load in the last batch; it sounded like a complete misfire but the primer had clearly been struck and the bullet had been started into the throat far enough that driving it out deformed the exposed lead. Lesson learned. I won't be trying to set any more speed records.
I also encountered quite a bit of vertical stringing with my scoop-only loads, so I'll be weighing everything from now on unless the zombies are closing in. Minimum loads shoot OK group-wise, but now that I've found my handloading feet again, it's time to put a bit more "oomph" behind things and see what happens.