Nomercy - You may prefer heavy and slow slug, but your example about the brick and marble is not based on Physics. Two objects regardless of weight and size dropped from the same height will travel at the same velocity and strike your foot or ground at the same time. (Aside from the resistance of air.) So in a vacuum, even a feather and a brick or piano will travel at the same velocity dropped to the ground. Don' t you remember one of the guys who went to the moon tested this law of Physics with a hammer and a light object (maybe it was a feather) there?

I think in order to test your theory you' d have to make some test shots in a material similar to an animal' s body. I think without question if you compared the effects of a slow heavy slug like a vintage .50+ caliber muzzleload to a 180 or even 150 grain ultra magnum load you' d be amazed at the greater damage the ultra magnum or other high velocity load would cause.

Or if you want to stick with your brick and a smaller weight object example. To make it a good analogy you' d have to drop the brick from waist high on a target and a golf ball from 300 yards high (where the velocity of the ball would be greater). Don' t drop it on your foot through, it might put you in a cast for awhile.