I will try and sum this up as simply as I can based on all the good posts so far.

First of all the arrow is in constant deceleration even before it leaves the string. If you ever look at a draw cycle curve you should be able to clearly see the point at which this happens.

Secondly I agree whole hardily that the shot placement is about 90% of the penetration equation.

Now to answer the original question. Penetration is best quantified by looking at momentum. KE is nothing more than number value of how much energy the arrow can deliver.

Think of momentum this way....we all agree that a heavy and light arrow will produce almost identical KE shot from the exact same bow right? The difference comes in downrange where-as the arrow that can maintain the most of its starting speed will also retain more KE right? Momentum is very similar.....its really a way to quantify a moving bodies resistance to change. This does not always mean that the heavier projectile will have more momentum when shooting through an animal though! A lighter narrower smaller arrow may actually win out based purely on the fact that the medium in which you are shooting through (animal flesh) will have less effect (drag) on the smaller surface area to slow it down. This is very similar to the effects of air on an arrow, and it coralates the speed and KE loss downrange.

I hope this helps....

Happy Shooting!




>>>------Tony Virnoche------>>>
>>>---The Archery Program--->>>