The graph above compares the trajectory of an arrow and a bullet. Comparing the difference in drop, bowhunting is a close-range sport that remains in the primitive spectrum. Before an arrow can penetrate a target, it must be directed toward that target accurately and in a manner that ensures that it is flying straight and true. This is necessary in order to direct the kinetic energy of the arrow along its longitudinal axis and precisely behind and in the line with the axis of the broadhead. If the flight of an arrow is characterized by fishtailing or porpoising some of the arrow s energy is dissipated and penetration is reduced.
Kinetic energy plays a major role in penetration.
A lighter arrow will, through increased velocity, maintain nearly the same level of kinetic energy as a heavier arrow.