This is my first time reloading for 300 Blackout but not my time reloading. I'm using Hornady's New Dimension Custom Grade dies in a L-N-L progressive to convert .223 cases. The problem I'm having that a newly sized case will fall right in to case gauge, but it stops short of seating flush with the case gauge face. It's as if the shoulder is too high on the case. As you can see, the die is seated so that it's barely touching the shell plate. At this point, I'm not sure if the sizing die is defective or if the case gauge is defective. I don't have any factory ammo to completely rule out that it's the case gauge. I'm thinking it might be a die issue because I can't twist the bolt when the case is chambered (the barrel isn't in the upper yet - AR build). Is there anything else I can do to rule out a die problem? I want to make sure I'm thorough in my troubleshooting before calling Hornady.