I have an RCBS ammomaster and have a charge-checker die. Although it doesn't lock out the shell plate from continuing to index, it provides a pretty accurate visual. It is a plunger that you set a rubber o-ring to the correct height for the charge. Each ensuing round goes through this checker and shows you by meeting the o-ring, that each round is correctly charged. Simple, but it still relies on the operator to catch an issue.
I use statistical process control on my powder station to ensure it is operating within expected capability. This along with the checker do a nice job.
