I have thought about taking one of the presses, dies and some premeasured powder charges to the range with the 6.5-284 and shoot a group using the same piece of brass and see how many times I can reload it with the Collet die and what the group would look like just using one piece of brass. Would all be cold bore shots by the time I reload between each shot.
That as the reason I brought it up really. I have done sorta what you are talking about. I took 9 pieces of 17 Rem brass and neck sized over and over as that was all the brass I had right then. It never got to the point of being hard to chamber and the necks started splitting at 9 reloads so I trashed all.
Repeated again with 10 pieces same results although I lost a couple to loose primers along the way to 9 reloads.
I have 221 FB brass that has been neck sized a bunch and while it is a little stiffer than original stuff I have never felt I needed to bump shoulders.
Not trying to make any particular point except don't think if you so neck sized that after a couple of loads you WILL have to FL size