Paul,it is not easy to compare bullets with arrows.Speaking of energy and velocity the difference between both is enormous but when we take into account the proyectile weight and the design of it the arrow is capable of making a massive wound channel.Also a bullet can do it ,but the effects of arrow after it hits the animal properly(good shoot placement)are different from a bullet.
A high velocity bullet generates "cavitation" inside the animal.A bullet will destroy or damage any tissues which it penetrates, creating a wound channel. It will also cause nearby tissue to stretch and expand as it passes through tissue. The arrow do not have bullet´s stopping power but is capable of making a wound channel with less damage tissues around it.The way the animal dies is different in both cases.I can affirm that the taste of a wild boar hunted with bow and arrow is better.
Dr. Ed Ashby has invested 27 years in the study of arrow performance and broadhead lethality. His testing is the closest thing to the scientific method as is possible under the testing conditions
Link:
http://www.alaskabowhunting.com/Dr.-Ed-Ashby-W26.aspx
Some words from Ashby broadhead study:
Based upon outcomes observed during the many years of the
Arrow Lethality Studies, I have several criteria for what
makes a really good broadhead. They are: (1) the blade must
have reasonable metal thickness; (2) that it be of very good
quality steel; (3) that it neither bend nor break when hard
bone is hit; (4) that it have a Rockwell scale hardness from
fifty-two to fifty-seven; (5) that the steel from which it is
made will tend to break before taking a bend; (6) that it have
a long and narrow shape (high mechanical advantage); (7) that
the ferrule taper is long, and fades very smoothly into the
blade; (8) that there are no abrupt junctures anywhere on the
head, and (9) that the blades have a straight taper cutting
edge.
For each of these criteria I have a specific reason