The so called "knock down power" is a myth widely over-rated by numerous hunters. You have to get in to the physiological/biological issues that cause death in a creature...Namely, blood loss, or trauma to a vital area of the nervous system that causes imediate sessation of life. The shock trauma is often what causes a deer or other animal to drop in it's tracks. In most cases, it has to do with spinal or cerebral penetration of bullet or flack. Flack being bone or bullet fragments. Occasionally, a heart shot will generate the same reaction. It just depends on numerous variables. In bowhunting, unless a deer is hit in the spine or brain, the animal ALWAYS runs. Yes, ALWAYS... an arrow travels too slowly to create the so called knock down power. It kills by bleeding the creature out. Cut a 1.5" diameter hole through 2 lungs, and see how far you go. You're toast. With a bullet, there is a shock waive that travels around the super sonic object. This shock waive creates a tremendous amount of damage behind the bullet as it passes through organs...which are mostly water. (think of the after effect of a drop of water landing in a glass...) As the bullet hits bone, it fragments. These fragments get intrained in the shockwave as it travels through the body, along with bullet fragments. These fragments cause additional damage to the internal organs and create the devesitation you see when you dress your animal. If knock down power were all we were concerned with, All hunters would be shooting heavy, full metal jacket constructed bullets. The so called knock down is created by
CONTROLLED FRAGMENTATION as the bullet passes through an object, or in this case organs. This is why no hunter in their right mind would shoot an FMJ unless taking strictly head shots. A 224 cal bullet traveling around 3700+fps at point of impact is creating a TREMENDOUS shockwave that creates a trendous amount if internal organ damage. This is the simple version. If you really want to get into all the physics, I'm sure there is an engineer out there that can expand on my "symplified" explanation.
