Physics dictate that the lighter an arrow, the faster it’s propelled. There are advantages to going lightweight, however, there are disadvantages as well.
Advantages of Lightweight Arrows
Fast arrows have flatter trajectories than their heavier counterparts. As such, they’re more accurate as the target distance increases and miscalculations in target distance are minimized by flatter trajectories.
However, lightweight arrows have a propensity to be much louder than their heavier cousins. This is due, in part, to the fact the bowstring moves significantly faster, disturbing and displacing more air than a slower string (on heavy arrows).
**Advantages of Heavyweight Arrows **
Heavyweight arrows soak up more energy than light arrows. With more energy being transferred to the arrow, less is converted into unwanted side effects, like noise and vibration. Heavier arrows carry more energy downrange in the form of kinetic energy which out-penetrates a lighter, less-powerful arrow.
Matching Speed to Target
While pursuing smaller, faster game, like whitetails, it’s advantageous to shoot faster arrows as they have smaller vitals than larger animals like elk. Small vitals require more precise arrow delivery to be fatal. In addition, small-bodied animals are more easily penetrated than large body animals.
When pursuing large animals, it’s advantageous to shoot slower, heavier more penetrable arrows as they have larger vitals and are more difficult to pass through.