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Kinetic Energy (You're Doing It Wrong)

Any bowhunter that tells you "KE is King" - is either uninformed, misinformed,  or a target pro parroting their sponsorship obligations. The following case study dramatically displays why the bowhunting industry and bowhunters have incorrectly applied Kinetic Energy (KE) as a determining factor in arrow penetration and lethality.

Here is the story of how the measurement of Kintec Energy came to be and what it was (supposed) to be used for.........In the late 1940s, US military trauma surgeon Dr. Frank Chamberlin researched the theory of shock waves produced by bullets traveling over 2500 fps. The term used to describe the “wave” was Hydrostatic Shock and the formula used to measure the bullets potential “wave” was Kinetic Energy (KE). Chamberlin never intended the KE formula to be used to determine bullet penetration.

Instead, Chamberlin determined that KE kills through the hydraulic effect “shock wave” the was produced by a supersonic projectile. Hydrostatic shock kills by trauma to body cells, not by hemorrhage from bullet penetration.

Incorrectly benchmarked in bowhunting, KE has absolutely no indication of penetration or for measuring tissue destruction protentional in projectiles traveling less than 2500 fps - ABSOLUTELY NO STATISTICAL RELEVANCE.

On the other hand, Dr. Ed Ashby’s 30 years of arrow penetration research quantified momentum, arrow mass, and forward-of-center (FOC) as true predictors of penetration at arrow impact. Ashby’s research especially holds true when a heavy bone is encountered. Arrows and broadheads kill through laceration (hemorrhage) created by penetration - not a hydrostatic shock. The deeper an arrow penetrates, the higher the chances of lethality and animal recovery.

This unlucky 100 mph pitch helps demonstrate our point. The government of South Africa requires bowhunters to produce 80 ft/lbs of KE to legally hunt Cape Buffalo. This is the only arrow or broadhead requirement.

If a major-league baseball weighs 2300 grains and we follow the KE formula:

2300 grain baseball x 147 fps (100 mph) = 114 ft/lbs of KE

Solely using KE as a benchmark, any MLB pitcher that can throw a 100 mph legal to hunt Cape Buffalo with a baseball in South Africa.  Ask yourself, how do you think this "KE legal system" is going to work out for the pitcher?

Why do so many bowhunters misapply the KE formula to determine arrow penetration knowing KE holds no relevance for measuring sub-2500 fps projectiles? Doesn't it seem counterintuitive to build an arrow system based on a formula developed to measure hydrostatic shock (which can't be reached) and not arrow penetration?

These are all good questions.

In contrast, at GrizzlyStik we focus on arrow FOC, total arrow weight, and momentum as benchmarks to determine arrow lethality.  Below is a 4-minute case study of our GrizzlyStik system at work on Black Death.  We think this is a perfect example of why we place no value on KE as a determining factor in arrow penetration.  KE either holds statistical relevance or it doesn't, and for us, KE draws no water in bowhunting.