His pressures must be sky high to get those velocities and he could probably make a 223 into frickin laser beam! He makes Gav's reloading efforts look quite conservative.
I see that AA1680 doesn't cut the mustard in 22 Hornet, but it is amazing in my 17 Hornet. I can get 20gn bullets to 3900fps and 25gn to 3500fps with wrecking the brass or my face, though the loads are wildly over book max.
I only ever got to 3570fps with a 40gn out of my 223 and thought that was pretty hot. I must try harder.