I had earlier complained about a WCC headstamp brass (Western Cartridge Company) that would not swage on my 1050 and would not accept a new primer. I have had about a dozen of these over the past few years, and today another one appeared and I thought to take pictures. I had tossed all the others.
As per the top cartoon in my graphic, a normal pocket on
commercial ammo has a radius-ed primer pocket. This radius helps guide the primer into the pocket during seating.
Your WCC is
military grade brass. To meet the specs of the NATO, the primer is crimped into place. You can see the circular crimp in your photo. What the crimp leaves is a sharp ledge that prevents reloaders from re-inserting a new primer.
As per the middle cartoon in my graphic, it's small, but you can clearly see the sharp ledge we're talking about. This is great brass, but to reload it the reloader must FIRST remove that sharp ledge. This is done either by swaging the primer pocket with a special tool to add back the radius,
or simply using a common countersink cutter to add a bevel to the primer pocket entrance, as per the bottom graphic.
Hope this helps.