A couple of data points
Allan Hall won the light 200 at a past Super Shoot using X-Terminator in a .22 something. As the Ramshot powders were kinda making a debut at that event, I shot the same agg Allan won using TAC (6PPC) and did quite well - won some money. I think it was 1999.
I kept on shooting the TAC and at the 2000 nationals (St. Louis if I have the year wrong) it worked OK. Something like 3rd, 4th, and 6th in the two, three and four guns respectively. Somewhere in the time line I placed 4th at the Super Shoot with the same stuff. Lot #50 it was called based on a little sticker pasted to the bottom of the jug. Couldn't agg with anything other than #50.
Suddenly, my success ended as it always does and did not swing upward until I set my beloved TAC aside. Anecdotal as it sounds, others that were shooting TAC experienced the same - both of them.
Two trusted competitors with extreme longevity in benchrest competition stated without collusion that ball powders would raise you to an admirable height and then throw you to the ground resoundly. Those are my words...I think they said something like "Don't shoot that stuff. It works good and then NOT!"
"Thrown to the ground resoundly" is what actually happened to me.