Yes - BUT --------
Speed does kill.
It's a whole lot more complicated. We're considering both internal and external ballistics. The one missing element in your query is shot placement. That's paramount.
If you gut shoot an animal speed doesn't mean much. Same with a rump or leg shot.
The explosive effect of fast, lighter bullets certainly does produce a seriously effective "hydraulic shock" that is proven dramatic". This is not only seen in ballistics gel but also in animals. It shocks the system big time. But doesn't necessarily have to be the primary cause of demise.
The way ballistics works it that certain powders produce certain speeds, feet per second, and certain pressures. Faster, lighter bullets travel further with less 'drop" so with long range shooting - past 300 yards, they come into their own. And I speak too about ultra distances, snipers - 1,000 yards, a mile.
As I related recently our ancestors exterminated over 42 million bison is just a few decades shooting primitive rifles using black powder at various ranges including 600 yards.
Too 12 gauge rifled slugs travelling at 1,200 - 1,500 fps are devastating at closer ranges.
As I also related recently, an exhaustive study of various bullet expansions, different types, different constructions, lead, clad, solids, copper, showed essentially expansions that couldn't amount to a hill of beans as far as the photos were concerned. They all looked basically the SAME - to me.
Another aspect is energy dump. Within the animal or pass through, clean exit on the other side. Barnes loading manual shows a study wherein exit wounds are significantly more effective and cause shorter "runs" after being struck. They bleed more and leave blood trails better too for tracking.
Consider also that a caliber, say .25, .27, .30 bullet that expands 50% can be reproduced diameter/dimensionally by simply shooting a larger caliber rifle 50% bigger than the base case.
Way back when I was a young guy I moose hunted with a .25-06. I spined it and dropped it in its tracks. Many years, and rifles, later I moose hunted with a .338 Winchester Magnum. I spined the moose and dropped it in its tracks. Both shots were in the range of about 200 yards. I had zeroed my scope at 200 so it was dead on at that range. The .25-06 was a light bullet around 100 grains or so. The .338 Mag was 2 1/2 to 3 times heavier.
So the answers to you questions are that one size DOES NOT fit all. It depends on the hunter, his personal beliefs, philosophy, range or distances he/she is/are shooting.
Generally, however, up to 300 yards, the heavier bullets, at slower speeds *( necessitated by the consideration of maxing out on the guns safe pressure ratings ) are more effective than lighter, faster bullets because they carry more energy and oomph.
The Weatherby's are an example of really fast as are numerous proprietary and custom brands. They are certainly more effective and better killers. But they burn out barrels faster.
A .30-06 is completely effective for killing an elephant with a head shot and it has been done.
A bow and arrow is/are completely effective in dispatching all sorts of animals with energy and velocity that is but a shadow of a good rifle.
So the bottom line is that you can kill game with just about anything including a .22 short rim fire *( Which I have done on the farm with pigs ).
Last edited by William_E_Tibbe; 08/31/15.
