it's not that simple. velocity has always been the "easy" way to gain extra muzzle energy but you have to factor momentum in here too. and because of momentum and because of what we are asking our bullet to do, a larger bullet mass will always be the most efficient way to deliver that energy into the target.

think about this: when it enters a game animal, both a zippy light .357 magnum bullet and a slower 250 grain .44 (both with the same muzzle energy) will expend energy as it moves toward the vital areas. when the bullet finally gets to the vital areas, the heavier.44 bullet will have more of its original energy remaining because it had more momentum to begin with.

bigger bullets are always going to preform better so long as you can easily pack them around. the 44 special is so "special" because it's a well-balanced cartridge (in terms of bullet size and chamber pressures) and that results in a well-balanced gun (in terms of weight & size). some would argue that the 44 magnum corrupted that balance.