I read somewhere or another that ( at one company or another) the only difference between their bench rest and standard primers were the personnel that made them. now i remember it was in a recent issue of Handloader magazine
I talked to a Bud who works in ammunition gaging.
He told me that priming compound is mixed by individuals. That today's "Mules" have up to 20 data ports and can measure primer flame, duration, intensity, material ejected, and probably a bunch of other parameters that I forgot.
He also said that match primers are made from the most consistent tested primer lots. This might be ATK he was talking about. He also said, the worker who made the most consistent lot is given a cash award, incentivizing them to do that again.