LocaCarnivore Expert: How Powerful a Hunting Rifle Do You Need?

How much power do you need in a hunting rifle?  The obvious answer: enough.  So, how much is enough, and is there such a thing as too much?  The first part is somewhat complex, with different factors important at different times.  As to the second, based on my decades-long hunting experience, I don't think there is too much gun for most big game, just too much bullet.

Let's look at how to match guns to game.  The most significant factors are the animal's body mass, not just weight, but how the weight is proportioned; hide thickness, including any fur; animal toughness--how it responds to wounds and how determined it is to live; and the hunting terrain--how far can it run it before the hunter's recovery probability drops below 95 percent.  Then there is the expected range for a shot, the hunter's tolerance for recoil, and how much said recoil affects the hunter's accuracy.

How Bullets Kill Game Animals (Warning: May Contain Science)

Before we answer those questions, hunters must understand how bullets affect a game animal.  A bullet must damage enough vital organ tissue to cause profuse bleeding.  Then blood pressure drops below a point where the circulatory system can't provide sufficient oxygenated blood to the brain.  The animal then loses consciousness and the autonomic nerve functions, those functions which operate the heart and lungs, stop.  Death is almost immediately afterward.

The time this process takes depends on which organs are damaged by the bullet, and to what extent.  A small wound to the lungs (either shallow or small in diameter), for example, may take hours, perhaps days, to kill.  A deep, wide wound to the heart or lungs will cause massive blood loss; unconsciousness and death will occur within a few seconds to a few minutes.  Some animals can still run a significant distance even in this short time, though.

The only way for an animal to fall straight down is if the central nervous system (CNS) is damaged enough to interrupt the signals from the brain to the legs by trauma to the brain or spinal cord.  With a head shot, the brain's signals to the heart and lungs stop, and the animal dies in short order from cardio-pulmonary arrest.  The video below is a perfect example how a spinal shot works (warning: graphic).


Animals which seem to fall immediately with a bullet placed high in the chest cavity are not "dead before they hit the ground." Rather, the spinal cord's electrical signals have been interrupted either by direct impact to the cord or hydrostatic shock from the bullet's energy as it passes near the spinal column, which inhibits the animal's motor coordination.  In this instance, death actually occurs shortly after due to blood loss in the lungs.  I've seen this effect first hand many times with powerful cartridges such as the .375 H&H and .300 Winchester Magnums at ranges less than 100 yards.

Animals will often fall straight down if a major structural bone in a leg is fractured or the shoulder joint is destroyed, but unless a major artery is severed, the animal will remain alive and require a follow up shot, or shots, to the thorax (chest) or cranium.

The Golden BB

So, how do we induce enough trauma for a quick, humane kill?  Either you hit the brain or spinal column (a difficult shot under the best circumstances), or you drive a wide, deep wound into the thoracic cavity to cause major bleeding from the heart, the lungs, or both.  A gut shot will only cause quick incapacitation if a major blood vessel such as the hepatic artery is severed.  Leg and neck shots only work if you cut a major artery, or in the neck shot's case, hit the spine, so they are not good alternatives either.  Famous gun writer and hunter, Wayne van Zwoll, has some advice on shot placement and common sense in this video.

Moral: hit them in the forward chest area with a bullet which has sufficient energy to drive through the heart or lungs.

Did You See What Happened to that Poor Little Bullet? (More Science)

Most hunting bullets expand when they hit something which offers enough resistance, such as an animal's hide.  Expansion begins, in most cases, within the first one to three inches after the bullet penetrates the skin.  This has two effects.

The now wider bullet traumatizes more tissue than it would if it had not expanded.  This creates the permanent wound cavity, ie. the "hole."  The wider, the more blood loss in general, especially in lung tissue.
Expanding bullet's path through green wood illustrates the permanent cavity.  Bullet entered on the left and exited on the right.  Recovered slug was almost twice original diameter.

The expanding bullet also transfers its energy to the animal as a shock wave.  This energy transfer, or "dump," makes the temporary wound cavity.  Visualize a balloon which inflates at almost explosive speed inside the tissue.  The wider, deeper, and faster, this takes place, the more tissue is displaced, or even destroyed.  This balloon effect takes place along the permanent cavity's axis.  Here's a video which shows a high-velocity rifle bullet making a temporary cavity in ballistic gelatin, a substance which mimics animal tissue.

Dramatic, isn't it?  The temporary cavity collapses once the bullet has passed through.  The tissue then assumes the shape and size made by the permanent wound cavity.  Temporary cavities can do substantial damage; they tear the surrounding tissue apart and can tear blood vessels.

Thus, the bigger the bullet, or the more and faster it expands, the larger both the temporary and permanent wound cavities created.  Also, if the bullet it traveling at least 2600 feet per second (small and medium bore rifles, 2100 fps for big bores) when it hits, it can cause hydrostatic sock to the CNS, which can kill if the autonomic functions are stopped long enough, but you should not rely on this effect.  A side note, handgun bullets in general do not cause hydrostatic shock; they have insufficient velocity and energy.  Their primary wounding mechanism is trauma from the permanent cavity, similar to how an arrowhead kills.
A controlled expansion bullet's nose "mushrooms" halfway down the shank and stops like this 260 grain Nosler AccuBond fired from a .375 H&H into test media.


Bottom line: how much vital organ tissue is destroyed controls how fast game will die.  You need a bullet which will both expand and penetrate to do this.

Welcome to the Real World

So how does all this nifty science help us hunters choose the right gun for the right game?  At a minimum, you need to drive a bullet at least halfway through the animal's chest, and make a permanent wound cavity 1.5 times wider than the bullet's nominal diameter.  How hard could that be?

Turns out it can prove difficult under many circumstances.  Every hunter knows (or should know) the best shot to take is with the animal facing broadside to them, and to place the bullet just above the front elbow.  This ensures at least the lungs are hit, and probably the heart as well.  Buuuuut...
Animals seldom give hunters perfect broadside shots like this Montana mule deer.


Animals aren't trained to just stand there and wait for you to make the perfect shot.  They move around.  They face head-on.  They face quartering away.  In short, they do just about everything but what you want.  This means you should have more than the minimum gun needed or else you'll have to pass up many shots.

Even a slight change in shot angle changes things drastically.  You'll need more gun than you think to punch through this big bull elk's tough shoulder and reach his vitals.

Lowest Common Denominator

Game animals are divided into categories from small to extra-large, and non-dangerous or dangerous.  Most classification systems are based on animal weight, and this is a good start point.  However, in my experience, other less quantifiable factors come into play as well.

For example, an American whitetail deer and a pronghorn antelope are both considered "medium" class game (90 - 300 lbs), and from a pure mathematical standpoint, a gun which will kill one will kill the other.  However, anyone who has hunted both species extensively will tell you a pronghorn is a far tougher animal.  They're not bullet proof, but the speed goat will run a long way if shot with too little bullet energy or the wrong bullet, and if the CNS or supporting bones are not damaged.
Pronghorn evolved in a tough 'hood with saber-tooth cats, cave bears, and other fierce, now extinct predators.  Underneath they have thick bones and an unparalleled will to live.

In my opinion, cartridges similar to the .243 Winchester (a classic whitetail round) can prove under-powered for pronghorn if anything less than a perfect shot is made or if the animal is too far away.

Same goes for elk and moose, both large class animals.  Moose are not difficult to kill, as long as a reasonable quality bullet hits them in the vitals, they'll go down quick.  Elk, on the other hand...  Elk are bullet sponges.   One in particular I remember, took a solid hit from a .340 Weatherby and just walked off as though nothing had happened.  Yes, it did die, but after a quarter-mile journey up a mountain in foot and a half-deep Colorado snow!

A Real World Solution

Here are the factors I weigh to decide how much is enough gun for a given game animal.

Bullet Impact Energy:  

Most experts claim 1000 - 1200 ft-lbs. impact energy is the minimum energy needed for a humane kill on medium game, and 1500 - 1800 works for large game.  You'll get some disagreement from the long-range hunting crowd (they're good folks, don't get me wrong) who believe the newest long-range bullets bring the threshold down 200 - 400 ft-lbs for each category.  They may have a point, but I lean to the conservative side on this issue as I don't want to botch the business at hand.

Therefore, take the maximum range you anticipate you'll shoot a critter, use a ballistic calculator for your intended load, and find the range at which it delivers the minimum recommended impact energy for the animal's class, and there's your minimum gun for said range.  I then want at least 20 percent more power in case I have to shoot under less than ideal conditions.

Bullet Construction:  

Remember what I said at the beginning?  What people think is too much gun is often just too much bullet.  The bullet is what does the actual work on a game animal, and it, more so than the cartridge, determines the final results.  Also remember no cartridge or bullet will make up for shooting animals in non-vital areas.

For most big game, select a controlled expansion bullet which balances expansion and penetration.  These bullets have some built-in device which stops expansion about halfway down the bullet's shank, either a partition of some sort or a much thicker jacket.  They also have the lead core bonded to the jacket in most cases, and some are made from a homogeneous metal such as copper.

A controlled expansion bullet will dump energy into the animal in the critical first 4 to 14 inches of penetration and then drive on to make a deep permanent wound cavity and often exit on the animal's opposite side (which leaves a good blood trail if you have to track them).  They also hold together if they hit a large bone or joint.  These are the only choice, other than solid, non-expanding bullets, if you are after dangerous game.
(L-R) Nosler Partition, Nosler AccuBond, Sierra Game King.  Both Noslers have designs which limit expansion, the Game King does not.  The Game King is better for long-range, the Partition excels on tough animals at short and medium range, and the AccuBond is more an all-rounder.

Thin jacketed, fragile bullets deliver explosive expansion on contact which is useful on lightly muscled animals like whitetail or roe deer, but they can leave gaping exit wounds and damage much meat if they hit the larger muscles or bones.  These are the bullets which make people think the cartridge is too powerful.  Also, they do not penetrate enough on large game such as elk, moose, red stag, kudu, etc.  Instead, they can cause a nasty but not immediately fatal, superficial wound.  At long ranges, where velocity is lower, these bullets come into their own and expand better than the controlled expansion variety.  Again, it's important to choose the right tool for the job.  Use controlled expansion bullets for most game at ranges less then 400 yards and rapid expansion for longer ranges or lightly built game.

Keep in mind you can adjust a particular cartridge's terminal performance by changing bullets.  Take the .375 H&H Magnum, for instance.  Although it's considered a classic African safari cartridge, it is suitable for any game from antelope up to elephant; it all depends on the bullet selected.  Loaded with a 260 or 270 grain controlled expansion bullet like Nosler's AccuBond or Remington's CoreLokt, it will drop deer, elk, or moose without excessive meat damage because the bullet dumps just enough energy to kill but has so much penetration, it usually exits before it can tear the critter apart.  Plus, it can still punch length-wise through a medium or large game animal at any reasonable hunting range should you only have a front-on or quartering away shot.  Loaded with 300 grain controlled expansion bullets, the .375 will stop most dangerous animals on the planet, except elephant--300 or 350 grain solids are the ticket then.

Recoil:

After calculating how much energy your intended game needs and then selecting the right bullet, you need to consider how much recoil you are willing to accept to get the necessary terminal performance.  If you get slapped around too hard by your choice, your accuracy will suffer, and accurate bullet placement more than any other thing is what puts animals down quick and clean.

Recoil calculators are available free on the internet, so it's easy to predict how hard your new wonder gun will belt you.  Most people's accuracy drops off with guns which generate over 20 ft-lbs(free) of recoil energy.  If the gun and cartridge combination you want recoils harder, and you can't get acclimated to it, then you'll have to either increase gun weight or move to a softer recoiling cartridge.  The basic rule here is shoot the most powerful cartridge you are accurate with, load it with the best bullet you can find, and hunt at ranges which are inside both its and your limits.

Is That Your Final Answer?

So, how much gun do you need?  Enough--as long as you can handle it--plus 20 percent additional energy.  If you hunt more than one species at a time, take the gun best suited for the largest, and with a good bullet it should do the job on the smaller ones.  Better to have and not need, than to need and not have.