Tomorrow there will be a 30% chance of rain with the
possibility of scattered thundershowers which might spread from the
southern Freestate to the Mpumalanga lowveld. Talk about keeping
your options open! Well predicting bullet performance on an animal
that you are hunting can be pretty much like predicting the weather.
There are just so many variables involved.
Take a look at Figure 1. These .223 bullets (apart
from the unused one on the far right which is shown for the purposes
of comparison), were all recovered from the same species of animal
shot by the same ranger on the same day at approximately (give or
take 30m) the same range - but just look how differently they have
performed! What is going on here?
We here enter the rather unpredictable realm of
terminal ballistics where many of our expectations on how a bullet
will perform seem to dissipate into one big question mark.
Figure 1: Six 55 grain .223 bullets
recovered from blesbok and one unused bullet (far right)
A bullets flight path from the moment it leaves the
muzzle until just before it impacts with a target animal, assuming
its flight path is not interrupted by a twig or other unexpected
object, is reasonably predictable. With some experimentation the
marksman will know how much the bullet he is shooting will drop at
different ranges and how much it will be steered off course by a
The shape of the bullets profile (ballistic
coefficient) and its mass will be the main determinants influencing
how it will fly through the air as it is subjected to the onrushing
air stream and downward pull of gravity. Height above sea level (air
pressure), ambient temperature and humidity can be factored into the
equation and still make the impact point on the target reasonably
The moment the bullet impacts the target, however,
is the point where confusion sets in and hunters are often caught
unawares as the expected effect of their chosen bullet fails to
materialize resulting in either the animal running off, or in the
case of dangerous big game charging, when it (whatever "it" might
be) was supposed to fall down dead in its tracks!
What is this variable that is often not well
understood by the average hunter? Before we can begin to answer this
question we should first clarify what is supposed to happen when a
bullet impacts living tissue.
Figure 2: Bullets come in a bewildering variety all
designed for a specific purpose.
Refer if you will to Figure 2. Here you will see a
variety of bullet types and designs. They differ significantly from
one another in shape, mass and construction but all have one thing
in common. As hunting bullets, they were designed to kill animals as
effectively as possible.
Each bullet was however designed for a specific
application. In other words they were designed to be used on a
specific group of animals. Whereas there are differences in
construction with some having exposed lead alloy tips, others having
a copper alloy full metal jacket, polymer plastic tips, spitzer
(pointed), round nosed, hot core bonded, partitioned or whatever,
they can be basically divided into two groups expanding and
non-expanding bullet types.
The behaviour of any bullet once it hits and then
enters into the tissues of a living animal is determined by four
Bullet construction is one of the most important
factors influencing penetration. Here we can identify two main
animal types that ballistic engineers have in mind when they design
bullets for hunting them. The first group is relatively thin skinned
with a light to medium bone structure and the second comprises
animals with a thick, tough skin, large muscle muss and heavy bone
structure protecting vital organs such as the brain, heart and
Bullets designed for the first group are usually of
the expanding type consisting of an outer gilded copper layer
enclosing a metal alloy (usually lead and antimony) having its tip
exposed or having a polymer plastic tip. Some are also designed with
a hollow point. See Figure 3 for typical examples.
The design features of these bullets allow for the
bullet to peel back on itself on making contact with and passing
through animal tissue.
This is referred to as "mushrooming" and the reason
for designing it to work in this way is to increase the size of the
wound channel so that more damage is done and the animal will die as
quickly as possible. See Figure 4.
Now some bullets are specifically designed not to
mushroom but to enter and pass through animal tissue with little or
no expansion. The bullet is designed for penetration into vital
areas that might be protected by tough skin, muscle and bone. When a
bullet expands it loses energy and begins slowing up because the
wider diameter of the expanded bullet has a greater frontal surface
area and experiences greater resistance to forward travel.
Figure 3: Examples of expanding hunting bullets
Hence an expanded bullet will have less penetration
than a solid non-expanding bullet and might not be able to reach the
vitals and may even break up or fragment on hitting solid, dense
material like bone. These solids may consist of solid brass or a
core of heavy lead alloy completely surrounded with a jacket of
copper allow. Bullets like these are intended for big dangerous game
such as elephant, rhino, hippo and buffalo and examples are shown in
The impact velocity will also have an effect on
penetration. Too slow and the bullet is going nowhere. Too fast and
the bullet will disintegrate on impact causing a shallow "cratering
wound". Impact velocity determines the hydrodynamic pressure and the
effects on bullet deformation. But, over and above this it also
determines the amount of cavitation in tissue (creating a temporary
and permanent cavity) which is proportional to its kinetic energy.
The greater the cavitation the less the penetration.
Figure 4: An expanded .270 Winchester bullet recovered
from a blue wildebeest..
The shape of a bullet will have an influence on how
it passes through animal tissue. Spitzer bullets which do not deform
become unstable at normal hunting bullet velocities and will not
penetrate as far as round or flat nosed bullets fired at the same
velocity. Non-deforming round nosed bullets in turn will generally
have better penetration than flat nosed bullets but this depends on
the width of the flat nose and the radius of the round nose. Most
rifle hunting bullets today are of a pointed shape and are designed
to expand but the amount of penetration based on shape also applies
to them as well.
Now the foregoing might be pretty "ho hum" we know
it all, to all the ballistic aficionados out there but it brings us
back to our original question. Why do identical bullets, shot into
the same type of animal at approximately the same range behave
Now all things being equal the same type of
bullet, hitting the same type of animal at the same impact velocity
at the same range, one would expect all the bullets to behave in the
same manner and have the same effect on the animal and therefore be
predictable. But they dont and they often behave in the most
unexpected way. Look at Figure 1 again. Of the six bullets, two have
mushroomed perfectly (this was what most would have predicted based
on their knowledge of the bullets design), two have partially
mushroomed, and two have hardly mushroomed at all!
Figure 5: Solids for thick skinned, heavy boned
dangerous game. A monolithic (top) and a full metal
jacket (bottom) showing their "innards".
All the variables we mentioned earlier on which
effect bullet performance are equal barring the one which hunters
often neglect to consider when they predict how their bullet of
choice is going to perform on the animal they are shooting at. By a
process of elimination you should by now have figured out that the
final arbiter of a bullets performance which can negate all the
others, is the line or path that a bullet travels from its point of
entry to its point of exit or to the point where it finally comes to
rest within the body of an animal.
Bullet performance is most often tested on materials
such as ballistic gelatin, or wet phone books and this gives rise to
certain expectations. Valuable information is gained from these
tests. It has been shown for example in tests using a variety of
bullets at different velocities that increasing velocity (within a
range of 1600 3200 feet per second) has a tendency to decrease
The problem with these tests is that the material
used to measure bullet performance is homogenous and this can lead
to expectations which might not necessarily work out in reality
because animals are not homogenous. Ballistic gelatin might closely
approximate muscle tissue but is very different to horn, bone,
tendons and gas filled organs such as lungs or fragile blood filled
organs such as the liver, kidneys or spleen.
A bullet shot into an animal can follow very
different paths through materials of very different density and
strength. Bullets of any given construction and impact velocity may
have significant differences in performance depending on the part of
the animal struck and the shotline through the target. Let us now
look at some case scenarios to illustrate the point. Refer please if
you will to Figure 6.
Figure 6: Examples of shotlines through a
Let us set up a hypothetical case scenario. It is 30
years ago and a hunter is using a .375 H&H Magnum to hunt Cape
buffalo. He has decided on a Winchester 300 grain Silvertip bullet
traveling at 2600 feet per second to dispatch the animal with.
Assuming shots 1, 2, 4, and 5 were taken from different angles but
were all aimed at the heart lung area, shot 3 was intended as a neck
(spinal) shot and shot 6 was an abdominal shot that the hunter took
as the animal was running away.
Now at this point we are not discussing the merits
or demerits of the different shots. We are investigating the
possible way in which the bullets could perform and how the animal
would respond given the different shotlines.
A side on presentation in which the hunter aims for
the heart with a shot placed through the shoulder.
Path of bullet travel: The bullet forces its way
through a layer of tough skin, connective tissue and thick muscle.
It penetrates well and begins mushrooming. Now it encounters the top
end of the humerus which in the case of buffalo is a rather
substantial bone. The bullet expands fully but, because of the
increased resistance it slows significantly. It punches through the
bone and through the soft pleura (membrane) lining the thoracic
It now enters soft, air filled lung tissue and
passes easily through before hitting the heart itself, composed of
strong muscle. The bullet is fully expanded and the kinetic energy
is dropping off quickly but enough energy remains to drive the
bullet through the right lung before finally coming to rest against
the bones of the opposite shoulder.
Condition of bullet: Fully expanded (mushroomed)
and mostly intact. Moderate weight retention.
Effect on and response from animal: A temporary
cavity was momentarily created and a permanent cavity remained
behind in the bone, lungs and heart tissue. Severe bleeding
resulted, the lungs collapsed and the damaged heart stopped beating.
However enough oxygen remains in the blood of the mortally wounded
buffalo to live for up to three minutes. It might drag the fractured
leg and run off with pink frothy blood spewing from the nostrils or,
if it sees the hunter, and is that way inclined may charge and cause
some damage or even death to the hunter before it finally expires.
There was a clear blood trail to follow of bright arterial blood.
The hunter approaches the buffalo from slightly
behind and attempts a shot high up through the hind leg angling
towards the heart/lung area.
Path of bullet travel: The bullet travels
through tough skin and thick gluteus muscle and begins to expand. It
then hits the very thick and hard pelvic bone and fragments in a
number of pieces each of which travel a short way before coming to
rest in the pelvic or abdominal cavity. No vital organ has been
Condition of bullet: The bullet has broken up into
several pieces and failed to penetrate far beyond the pelvis.
Effect on and response from animal: No vital
organ has been damaged. The permanent cavity is short and not well
developed as the bullet broke up and the pieces formed small but
rather insignificant wound channels. Blood loss is not significant
(assuming no major blood vessel has been hit). If the pelvis is
badly broken the animal might not be able to run but may still pull
itself forward by using its front legs. If the pelvis is only
fractured or not badly broken the buffalo may run off (or charge).
If it runs off it will have to be tracked until another shot
(hopefully a fatal one) can be taken.
There will probably be a very insignificant blood
trail to follow (unless by chance a major blood vessel has been
hit). If the buffalo gets away and cannot be found it could over
time recover but may be crippled or if the wound is of such a nature
that severe infection sets in may die a slow, painful and lingering
death (especially if the bullet has lodged in the abdomen and
peritonitis sets in).
From a side on presentation the hunter places a shot
about one third way down in the neck, aiming for the cervical
of bullet travel: The bullet passes through the thick and tough
neck skin and then on through the powerful neck muscles. It then
breaks into and through the strong cervical vertebrae deforming
somewhat and losing some of the mushroom petals but pushing on
through the opposite neck muscles rapidly losing energy before
finally coming to rest just under the skin on the far side.
Condition of bullet: It has mushroomed well but
some of the mushroom petals have broken off and remained behind in
the vertebra. Weight retention is fair.
Effect on and response from animal: The animal
was immediately incapacitated as the spinal chord was severed. It
fell immediately to the ground and made no attempt to rise. There
was still some movement in the face and ears for a minute or two
before the animal died.
Here the hunter takes a quartering away shot from
the left side angling the shot forward to hit the heart and or
Path of bullet travel: The bullet penetrated the
flank skin, a relatively thin layer of abdominal muscle and angling
forward perforated the liver, the lungs, and the heart finally
coming to rest against the inside of the humerus fracturing but not
Condition of bullet: The bullet did not
encounter any hard material (i.e. bone) during its travel from entry
to exiting the right hand lung. By which time much of its energy had
dissipated due the long distance of travel. It mushroomed
predictably and by the time it hit the inside of the humerus had
enough energy to crack the bone but not penetrate it.
The bullet mushroomed well, retained most of its
weight, held up well when it hit the leg bone and was pretty much
intact on recovery.
Effect on and response from animal: The animal
responded by running off (or charging the hunter) but will die soon
of oxygen starvation of the brain as blood pours from the heart,
liver and lungs (all of which have been severely damaged). There
will in all likelihood be a good arterial blood trail to follow. It
may run for a couple of hundred meters before slowing and finally
collapsing to the ground as it sounds the mournful death bellow
characteristic of these magnificent beasts.
A similar shot as shot 2 but lower.
Path of bullet travel: The bullet penetrate the
rump skin and traveled a short way through thick thigh muscle before
hitting the femur a thick and very tough bone. It shattered the
bone dissipating most of its energy in doing so. The impact also
caused the bullet jacket and core to separate each traveling for a
short distance before coming to rest in the pelvic cavity.
Condition of bullet: Weight retention very poor
as the internal core and the copper jacket keeping the bullet
together have separated resulting in very poor penetration.
Effect on and response from animal: Perhaps (if
the hunter is lucky) the large femoral artery might be severed which
can cause the buffalo to bleed to death fairly quickly (there will
be a good blood trail). If not there will be no significant blood
trail to follow up and even with a broken leg the buffalo may run
off and lie in wait for the unwary hunter daring to follow up.
If the wounded animal cannot be tracked down it may
survive but be crippled and in pain or if severe infection sets in
eventually die after having suffered severe pain and discomfort.
From a side on shot presentation the animal gets a
fright and jumps forward a moment before the shot goes off. The
bullet hits far back in the abdomen passing well below the spine.
Path of bullet travel: The bullet enters the
skin and passes through a thin layer of muscle then through thin gut
walls with their watery content again encounters a thin layer of
muscle and exits the skin on the far side. During its passage
through the buffalo the bullet has encountered little tough tissue
and no hard bone.
Condition of bullet: The bullet has only
mushroomed to about a third of its capacity but has about 98% weight
Effect on and response from animal: A small
wound channel (permanent cavity) has resulted with little bleeding
and no vital organ or major blood vessel damaged. The buffalo ran
off looking a little hunched up or may charge the hunter if he is
spotted. The wound which has ruptured gut walls will cause abdominal
contents to spill into the abdominal cavity and cause peritonitis
which is generally fatal after a time and will cause the animal to
die a lingering and painful death if it cannot be found.