“Stopping Power” (rightly called Terminal Ballistics) is actually a very simple and easily understood topic that’s been muddied by over a century of Pseudo-Science and “wisdom” about bullet lethality.
Internet rumors about “Stopping Power” haven’t helped either. unfortunately, most of those discussions boil down to personal preference and opinion, not science and facts.
The truth is very simple and easily understood. and I’ll unpack it for you below.
Lets start with a “Stopping Power” Myth:
“Kinetic energy is an indication of Stopping power”
Example: a 490 grain Broad-head arrow traveling at 225 Feet Per Second (FPS) has a kinetic energy of 55 ft-lbs. A 1 Pound Gel filled bag launched at 60 FPS has a Kinetic Energy of 55 ft-lbs.
Which is more lethal?
Another example: The average football linebacker weighs 230 lbs and sprints at 25.5 FPS. That’s 2020 ft-lbs of energy. A 190gr bullet moving at 2200FPS produces almost identical energy. Which is more likely to kill an Elk?
See my point?
Energy is NOT a good indicator of a bullet’s lethality. Energy is simply the ability to do work. Nothing more, nothing less. It’s HOW that work is applied that determines how lethal a bullet is.
But I’m getting ahead of myself.
To understand how a bullet kills and/or incapacitates an animal (or human in the case of combat) You have to realize there’s only one way to stop an animal (or human) dead in it’s tracks.
You must Destroy or Disable the brain.
If the brain is functioning, it’s still issuing orders. Breaking bones can disable a portion of the body, but someone hopped-up on drugs or some of the tougher animals won’t care.
If you want “bang-flop” hunting success or to instantly incapacitate a hostile attacker/soldier, then you must Destroy or Disable their brain.
There are several ways to do this.
- Direct Destruction. (I.e. Hit it with a bullet. It’s very effective, but easily the hardest option)
- Disable/destroy the spinal cord. (which effectively disables the brain’s ability to control the body)
- Deprive the brain of oxygen. (Either by a sudden loss of blood pressure or by causing enough blood loss that they black out)
Now lets examine them in more detail.
#1 Direct Destruction
The brain is a relatively small organ in most animals (especially in birds, deer, and some politicians) Hitting it poses both an accuracy problem and an ethical problem.
Accuracy wise, it’s too hard to hit in a hunting scenario, and even harder in a combat scenario. Deer especially are prone to moving their heads quickly and without warning. Too often, hunters miss and destroy the animal’s jaw or inflict another painful, but non-lethal wound.
That leads to the Ethical part: I would never try a headshot on a game animal. If you destroy it’s jaw, it’ll probably escape and then die a long slow death by starvation, dehydration, or infection.
There’s no reason to take that chance when there are MUCH better options.
#2 Disable/destroy the spinal cord.
This is NOT the better option. The spinal cord is harder to hit than the brain. Again, the odds of inflicting a slow painful death on the animal are just too great for ethical reasons.
#3 Deprive the brain of oxygen.
This IS the better option.
If you hit an area with a Large enough concentration of blood (Like the heart/lung area) and punch a big enough hole through it. The resultant loss of blood pressure will cause rapid unconsciousness. (assuming the pressure loss is great enough)
The size of the hole needed is directly related to the size of the animal. Larger animals have more blood so it takes a larger wound to lower blood pressure enough to cause unconsciousness. More smaller holes can work, But remember this:
Your First shot is ALWAYS the most effective, especially on animals.
Because once the animal has suffered trauma (been shot), it dumps endorphins into the body which constrict the arteries specifically to Prevent Loss of blood/blood pressure.
Additionally, sometimes the hydraulic pressure from the bullet hitting a large concentration of blood can travel along the arteries and rupture the delicate blood vessels in the brain. This essentially creates a cranial aneurysm and virtually guarantees DRT (Dead Right There) performance.
But that REQUIRES hitting the heart/lung area with a bullet that does enough damage. Doing enough damage requires good bullets. So the winning formula is:
Good shot placement + good bullets
Wasn’t that simple?
Here’s How Bullets Deal their Damage:
There are only two ways bullets can deal damage.
- #1 The permanent cavity (Basically the hole left by the path of the bullet, a fragmenting bullet can make multiple holes)
- #2 The Temporary Cavity (In more powerful/better designed bullets, the area the bullet doesn’t directly touch but does cause damage)
The Permanent Cavity is simply the tissue that’s directly destroyed by the bullet as it travels through the body. Such tissue is crushed into oblivion.
All bullets leave a permanent cavity and it’s easily the most reliable method of inflicting damage with a bullet.
A Temporary Cavity is only left by larger and/or better designed bullets. The temporary cavity is can best be described like this:
- If you drop a pebble into a pond you get ripples.
- If you drop a 1 pound steel ball into a pond, you get big ripples.
The same thing happens when you hit flesh with a (well designed) bullet. The flesh is forced outward away from the impact point, just like the ripples in a pond.
Human tissue is elastic and will spring back. But if you make a “splash” large enough, you can stretch the tissue past it’s elastic limit. Tissue that’s been stretched past it’s elastic limit suffers damage ranging from light bruising to being essentially “pulped” by the force.
So yeah, pulp can be deadly. 😉
(one of these days I’ll write an article about how cavitation relates to the Temporary and Permanent Cavities… One of these days.)
How large/deadly is the Temporary Cavity?
That’s a bit like asking “how fast is a car”? It depends on what car we’re talking about.
The bullet’s velocity and mass are factors, but not the most important one. The most important factor for creating a damaging temporary cavity is the Frontal Shape of the bullet. The flatter the front of the bullet, the larger the temporary cavity. Larger and flatter frontal shapes create larger temporary cavities.
(This was first discovered the Emile Theodore Kocher in the 1870s. He is basically the father of modern would ballistics, even though few have heard of him)
Regardless, the temporary cavity is never very large.
We’ve all seen the ballistic gelatin pictures with the temporary cavity filled with a colored dye to make it more visible. The trouble is Human tissue is stronger than ballistic gel.
The penetration numbers are usually spot on, but the size of the temporary cavity can exaggerated because of the lower strength of the ballistic gel.
Measured from the path of the bullet, the temporary cavity decreases in lethality VERY quickly. Even at point-blank range, the temporary cavity rarely exceeds 2-3 inches in radius MAXIMUM with most modern small arms.
That number only reflects tissue that’s damaged.
Damage can mean only “light bruising”. Some inelastic structures such as the brain, heart, liver, kidneys, and a full bladder can be damaged further away, but not much further away.
Actual tissue destruction (Pulping) usually takes place at only 1-1.5 inch radius with most modern small arms.
As you can imagine, pulping all the tissue in a 2-3 inch cylinder through an animal can cause a rapid loss of pressure that disables the brain.
However, It still requires good shot placement.
Your shot can be off by only 1-1.5 inches before the temporary cavity won’t even help. Fortunately, the heart/lung area is large enough to provide a sizable target.
The temporary cavity makes good shot placement more effective. it does NOT negate the NEED for good shot placement.
In other words:
Shot placement is STILL king.
Even without a temporary cavity, the permanent cavity can still easily kill an animal (and sometimes quickly) if you hit the heart.
If you miss the heart, the temporary cavity can still cause damage, but NOTHING does the job like a direct hit. As an example, the United States Special forces have achieved 1 shot kills at 700 yards… with a 5.56!
Shot placement is King because you can’t miss fast enough to win a gunfight or fill a hunting tag.
That said, animals (and people) go down much faster with a temporary cavity. When hunters talk about effective range, it’s usually in reference to the minimum velocity needed for the bullet to expand.
- An expanding that expands leaves a wonderful temporary cavity.
- An expanding bullet that doesn’t expand doesn’t.
A bullet that tumbles can also leave a good temporary cavity, but those these bullets tend to veer off course more readily than an expanding bullet. An good example of a lethal bullet that tumbles is the 7N6 round created by the Russian military for the 5.45×39 cartridge.
That leads us to Handguns.
Unless it’s something like the .357 Magnum, 10mm or similarly high-powered handgun, you almost certainly won’t get a temporary cavity.
Because most handguns don’t have enough mass and/or velocity for even a GREAT expanding bullet to create one. That’s why pistols are Terrible weapons (compared to rifle and shotguns)
Even a shot directly through the heart with a handgun doesn’t cause enough pressure loss to make the target go unconscious. It will take at least 6-8 seconds for them to lose consciousness. (It takes that long for the brain to use up the remaining oxygen after blood has stopped pumping)
That’s plenty of time to shoot back or do other very bad things. This incident is a great example: Why one cop carries 145 rounds of ammo on the job.
The bad guy in that incident was hit with 14 rounds of .45 ACP. He didn’t stop until he was hit in the head. Also, “no evidence of drugs or alcohol was found in his system.”
He would’ve died eventually from the 14 wounds. But he continued fighting until he was hit in the head.
I repeat: You must destroy or disable the brain.
So to review:
You can only cause rapid incapacitation by destroying or disabling the brain.
The best and most effective way to do that is cause a rapid loss of blood pressure, which will cause the animal to blackout.
Headshots are just as final, but not as ethical for hunting. The ethics of self defense/war are a little different.
One more thing.
If I hear the term “hydrostatic shock” one more time, I’m going to scream.
It sounds very scientific and meaningful, but it’s definitely is NOT. Hydro means water. Static means “not moving”. Shock means force transmitted through a medium.
So Hydrostatic Shock means “The unmoving shockwave in water”.
Are you kidding me?
My Advice: Don’t rely on pseudo-science to achieve that mythical force called “Knock-down power” or “stopping Power”. If there is such a thing as “Stopping Power”, it’s caused Great Aim plus Great Bullets.
I’ve said it before and I’ll say it again: You can’t miss fast enough to win a gunfight or fill a hunting tag.