What you see in the increased costs of "Match" primers is to cover the additional quality control steps they are submitted to in order to help insure dependability and consistency. Of course, as with "Premium" gasoline, your personal experience and milage may vary.
As B'tube states, there is no difference in the primers. There is no quality control on the production of primers beyond what may be performed on the components. The assembled primers are packaged and shipped. The difference is that more experienced workers are used on the BR production line, with no differentiation in components, implying that there is less variation in the final product. That's it. What you purchase may or may not be better than the standard product, and vice versa.
To expand a bit on winchester 69s post, match primers are the first run of primers from a batch. They're made on machinery that was freshly calibrated, with chemicals that were freshly mixed. I do believe that all they are simply the primers from the first shift of a new batch. They are a little more consistent, but not everybody receives any benefit from that.
The only difference between standard and match/benchrest primers of the same number (such as CCI 200 and CCI BR2) is that the match/benchrest is made more consistently. There is no difference in brisance.
You will hear almost anything about match/benchrest primers, including that they're hotter, or cooler, or the cup is more scientifically made. But I have visited the factories and the only difference is that some workers are better at spreading the priming mixture more evenly, and those are the people that get assigned to make CCI BR's or Federal M's. Otherwise they are identical to CCI 200's or "regular" Federals.
The entry is copied from the 24HourCampfire site, and was written by John Barsness aka Mule Deer.