Not primers, but we were swamped with orders one year and kept running a piece of equipment that needed to do down for maintenance. But S&M (not Sadist and Masochist, but Sales and Marketing) demanded we keep running. Well one day it failed catastrophically. Instead of a 36-48 hour rebuild we were down for 5 days.
I doubt CCI would run out of primers if everything was running smoothly, but imagine a small explosion. Primers can do that. Or a piece of equipment that fails and parts are not readily available.