Protrusion looks fine now. Unfortunately, I did not pay attention to what it looked like in the fired position when I first disassembled. I'll go back to the range in the morning and see if this was actually the problem.
These are CCI LR primers, I've probably fired 500 of the primers out of this brick, this is the first issue I've had with not firing.
The spring is definitely not too soft. Considering I don't have a proper workbench, took some real manly grip strength to disassemble and reassemble.
I only have a neck sizing die for my 9.3x62, so I'm pretty sure the shoulder wasn't bumped back.
We will see what's what in the morning.
I'll see if I can fire what I have, but I'll put a couple CCI primers in the PPU brass and bring that with me to the range.