Why is momentum the most important measure of broadhead and arrow lethality?
In archery, momentum is largely recognized as the measure of how likely an arrow is to achieve a complete passthough against the target, such as a Whitetail Deer.
The greater the momentum of the arrow and broadhead, the greater the likelihood of a passthough, all other factors being equal.
However, the importance of momentum goes beyond that.
According to FBI ballistics data and research, momentum is a far greater predictor of wound channel damage and overall lethality than kinetic energy or hydrostatic shock.
Key takeaways from the FBI research in this area include:
Kinetic energy is an OK method to compare the damage a projectile can do to living tissue, but momentum is much better.
The FBI data shows that the correlation between momentum and wound channel volume was very high, with a correlation coefficient of 0.73, where 0 is considered no correlation and 1 is considered perfect.
On the other hand, the correlation between kinetic energy and total wound channel volume is only 0.35, which is considered low correlation.
See this chart for the data:
Therefore, momentum more closely associated with “stopping power” than kinetic energy.