There was once a poster here who was doing experimental work and trying to sell the results to the government. I forget his name. I think this was in the original format days MANY years ago. He has devised a duplex load (according to him) which got 8000 fps in a Garand and 10,000 fps in a Browning 50. The theory was to keep a nearly constant pressure until the bullet (or pleshette) leaves the barrel. This required a bull barrel as thick as the chamber area. It was a mixture of a $1200 powder and a $32,000 powder. The trick was for the pressure to increase as the volume increased behind the projectile resulting in a constant pressure behind the projectile. That way, the chamber pressure was as constant as possible. Neat idea it would make a Garand or Browning 50 a tank killer. Many it was real, maybe it was hooey, but the idea was interesting.
