A lot of hyperbole has been written about broadheads over the years. We’ve been schooled on their ability to withstand explosive assaults on plywood and car tires. We’ve seen the high-speed film of various heads blowing through steel drums. And while this makes for entertaining reading and thrilling footage, it gives us little quantitative data on a broadhead’s real-world penetration performance on game.
A broadhead’s ability to pass through an animal is directly related to its frontal profile, blade angle (including deployment angle on mechanicals), cutting diameter, sharpness, and the amount of kinetic energy the broadhead and arrow shaft carry at the moment of impact. Penetration is particularly critical 1) at longer shot distances; 2) when the arrow strikes obliquely; 3) when using lower draw weights; and 4) when pursuing game larger than whitetails.
The laws of physics dictate the amount of “work” an arrow has to do to penetrate a target animal (expressed in foot-pounds, inch-pounds, or joules). This work (W) is equal to the force (F) required to penetrate multiplied by the distance (D) over which that force must be exerted (W=FxD). The kinetic energy an arrow carries (as provided by the bow) is what affords it the ability to perform this work. When that’s depleted, the arrow’s forward movement stops.