I just examined a 30-06 blank..
that was fired at my BIL's funeral by an Air Force Honor Guard, and the neck of the case shows about 10 or 12 "cuts" in the case mouth about half the length of the neck, parallel to the long axis of the case.
If you will examine an unfired military blank you will see that the case mouth, having no seated projectile, is crimped shut tightly enough to prevent the loss of the powder inside it. When it is fired, the crimp is pushed open.
My conclusion is.. if nothing else, the necks cannot support a full load - not even a "starting load" as shown in reloading manuals.
Artillery lends dignity to what would otherwise be but a vulgar brawl.