What in the world do you consider fast? Here are some velocities from different bullet weights out of the .50bmg.
I consider using normal bullet weights for the gun that shoot over 3200FPS or so 'fast'. when off the shelf bread and butter 30-06 and .270's shoot right at or very close to 3k FPS, it seems more of a 'normal' velocity than a 'super duper blazing fast magnum' round. Sabots are a whole different story, which of course ups anythings velocity considerably. W/o a doubt the WEIGHT of the bullet that the .50 can shoot at 3k FPS is impressive, but the velocity figure itself is not IMO. Perception differs per person though a round at a mere 2k FPS would seem blazing fast to one who only shoots black powder weaponry....for example...