Refer to the table for your arrow speed. Use finished arrow weight expressed in grains and arrow speed in feet per second. It has been further suggested by several in the broadhead business that an extra 10 ft-lb should be added to each of these minimums when mechanical broadheads are used. These, of course, are only rough guidelines. Many animals have been taken through the years, and will continue to be, with well-placed arrows carrying much less energy.
Arrows come in many sizes and weights.
A heavy arrow will soak up more of the bow's potential energy on release and will thus increase the bow's efficiency rating. It will also make the bow quieter. This is why heavy arrows carry more penetration energy than lighter arrows - they soak up more energy from the bow. A good way to always be alert to wind direction is to attach a small duck feather to the limb of your bow.