6400 meters/second is pretty fast isn't it, Miller?
I had a dear friend, who shot flinters a lot and was a national champion in offhand competition, who used to bet percussion guys that he could load and fire more aimed shots in 60 seconds with it than they could with their cap lock. They would invariably take the bet. He could smoke them everytime, pardon my pun. He would load the rifle with a very light charge of 4F, then after seating the ball he would tilt the rifle 90 degrees to it's right side, bump the stock a couple times, and enough 4F would trickle out the touch hole to prime the closed pan. Then a quick mount and Bang!
I won't say how many he has gotten off in a minute, because I cannot remember for certain, but it was more than anyone would believe without seeing him.
All my best to you Miller, SRH