I plugged numbers into a program I have for 350 grains, 295 ft/sec, 70# peak, 8" brace and 100 grains of virtual mass and then given those initial conditions changed the peak weight to 78#, mass to 479 grains and draw to 27.5". The result was 257.0 ft/sec.

In order to get 300 ft/sec for 479 grains and 27.5" draw I had to take the weight up to 106.3#.