Kinetic Energy

Kinetic Energy is important for all bow hunters as it is the amount of killing power or hitting power our arrows hit the target with. Different areas have guidelines about the minimum kinetic energy needed to take big game animals. As a general rule of thumb for medium sized game such as deer, goat, antelope, and sheep, 40 ft-lbs. of Kinetic Energy is recommended. For large game like black bear, caribou and elk 42-65 foot-pounds will do the trick, and the tough thick hides of moose, brown bear, buffalo, and grizzly will require 65+ft-lbs.

So how do you know how much kinetic energy you have? Here is the formula:

(velocity x velocity) X arrow weight in grains / 450,250= ft-lbs. of kinetic energy

For example, I will do the calculation with  my setup. I shoot a  Bowtech Tribute set at 70# with a draw length of 27.5″. I shoot 5575 Gold Tip Pro Hunter arrows tipped with 100 grain heads. Out of the chronograph, I clocked my arrow shooting at 291 fps with an arrow weight of 361 grains with stock gold tip nocks.

make sure you chronograph your bow and arrow speed, as my bow advertises a speed of 338 fps but through the chronograph it shoots only 291fps.

so the calculation looks like this:

(291 x 291) x 361 / 450,250= 67.895

My current set up hits with 68 ft-lbs of kinetic energy.

Do the calculation to see how much power you are hitting your targets with.