The Wasted Energy Myth
This misconception seems reasonable on the surface: Bullets that pass through game waste energy that is merely spent in the dirt or some tree where they finally come to rest. The best game-stopping performance comes from bullets that pass through vital organs and nudge the far side skin with their last gasp.
Sorry, troops, but bullets don’t kill like Mack trucks. Those grand kinetic energy figures you see (like 3,600 foot-pounds [ft.-lbs.] from a 180-grain bullet thrown by a .300 Win. Mag.) don’t hold up in the real world. That 3,600 ft.-lbs. figure means there is enough energy in that fast-moving bullet to lift 3,600 pounds a foot off the ground. But do you think if you shot your .300 Win. Mag. straight up into a Toyota Corolla (2,822 pounds) it would fly more than a foot off the ground? Don’t try it at home; but on a safe range where it’s legal, shoot a rubber inner tube filled with 50 pounds of wet sand. My math suggests a bullet with 3,600 ft.-lbs. energy should lift that bag of sand about 70 feet. I’ve tried it. It doesn’t happen.
So, how much energy is wasted when a bullet passes through a critter broadside? I don’t know. But I did once use a chronograph to measure the speed of a 180-grainprojectile exiting 2-feet of ballistic gel. The bullet was fired with a .300 magnum, entered the gelatin going more than 2,900 fps carrying more than 3,000 ft.-lbs. of energy—and exited going 245 fps. The 20-pound block of gelatin wiggled and bounced, but wasn’t even blown off the table. The remaining bullet energy calculated out to be 27 ft.-lbs.
Now this doesn’t mean every bullet will exit every animal going that fast or that slow, but keeping it inside the hide isn’t going to make the difference between dead and alive. It is trauma, both immediate via physical contact with the expanded portions of the bullet and radial via the energy waves carried through the body that makes a bullet work. Sometimes this energy wave or cavitation damage, call it shock if you want, results in an instant kill, sometimes not. Central nervous system hits usually result in immediate effect, but heart-shot game can dash dozens of yards before falling blood pressure shuts down consciousness.
This is why bullets are built so many different ways. Some, like Ballistic Silvertip Varmint loads, combine lead cores wrapped in thin gilding metal jackets designed to break apart on contact, dispersing energy over a wide area with minimum penetration. Varmints after all don’t require the shock needed to bring down big game. Ballistic Silvertip big game bullets are wrapped in thicker jackets to improve penetration in larger animals, yet the lead core mushrooms easily and quickly to maximize surface area for increased tissue damage. AccuBond CT and Power Max Bonded bullets take penetration a step further by “welding” the jacket and core. This aids weight retention, which can enhance penetration. Monolithic E-Tip and Power Core 95/5 bullets use notched nose portions and brass shanks designed to expand predictably about 11⁄2 to two times the original bullet diameter while losing virtually no weight for extremely deep penetration.
Finally, the XP3 is a hybrid combining a bonded lead core in the shank with a hollow brass nose and polymer tip. This, too, loses virtually no weight despite massive impact energies, but the additional density of the lead core provides even more ballistic efficiency.
Each of these bullets can perform to perfection across a diversity of game and in a broad selection of cartridges. But none are guaranteed to kill faster and more efficiently if they lodge against the far side of a hide instead of shooting through it. Ultimately, how dead is dead enough?