Bulletsdo actually generate enough energy to knock down a deer. Problem is that these projectiles expend that energy over time and distance and in all directions and loose mass as they are doing it.

If you were to hit a deer with 3000 foot pounds of KE but that object was a 15 pound bowling ball moving at 120 fps the deer will be knocked right on its arse becasue all of that KE would be transfered to and absorbed by the deer almost instantly and the bowling ball would loose no mass.


But on to the original question. [8D]

Bowjacksons site is a great tool. There are a few things you need to know about your arrow first..... Fletch type and height and length, total arrow weight, arrow outsidediameter, initial speed out of the bow, and arrow length.

Plug all of this into their ballistics calculator and it will give you a good close calculation of what kind of energy and momentum your arrow will have all the way out to 100 yards.