Surely not as fast as Mwag, but this was me practicing years ago with a 416 Remington. The shellholder was made by my wife. I killed my first two buffalo with that rifle.
I never felt I was a better or worse shot with a bolt gun or single shot. I do know I am faster with a bolt gun on the second shot, the amount of movement required gives the edge to the repeater. My doubles are even faster.
That is some fine shooting @Mike70560 !