A quote from Anthony G Williams from his book on basic ballistics.
It is often claimed by hunters that as the striking velocity of the bullet increases beyond about 700 m/s (2,300 fps), so hydrostatic shock begins to appear, with the effect that animals drop dead much more dramatically than if hit in the same place with a low-velocity bullet. However, this effect does not seem to be replicated in people; there are many cases of soldiers continuing to fight for some time despite receiving severe (and ultimately fatal) wounds from high-velocity rifle bullets. Furthermore, serious shock effects are only likely if the bullet exceeds the speed of sound in flesh, which is around 1,500 m/s (4,900 fps), but even this has been disputed.