Mike D;
You are absolutely correct. I was trying to read real fast & somehow jumped that. I had read that for many years the proofing was all done with BP, but was thinking I had seen that the definitive proof had been changed. Guess that was incorrect. I believe the definitive proof is fired with a much finer grain powder than the provisional to give greater pressure in the chamber area.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra