I took my single virgin Hornady case, resized it with the Hornady 450B decapping die and measured the ID in .025 steps going in from the mouth. I took a once fired .284 case, resized it, cleaned it in my ultrasonic cleaner with the vinnegar/water/detergent mix from 6mmbr.com removing any deposits from inside and measured it the same way.
For my measuring device, I coated the inside jaw edge of my caliper with layout ink and scribed .025" increments with a second caliper like this:
What follows is my measurements, both numerically and in graph form. Draw from it as you wish in determining how you prepare your .284 brass.
The odd crossover that occurs at 1.2 inches length and all reading in further than that are compromise values. I discovered that due to the shape of the caliper jaws that after I passed an insertion point where the knife edge that measurements are based upon, it could not touch due to the combined thickness of the jaws hitting the case mouth. It makes it in a bit further without being conflicted on the 450b case due to the thinner wall at the mouth. So as long as you are only interested in seating bullets less than ~.45 inches depth, the measurements are useful.
Hoot
