Stopping Power, Shot Placement, and Other Basics

 When discussing defensive gun use, there are a number of crucial factors that can't be covered in a tweet.  This entry will touch on the ones I find important, with the intent of providing practical knowledge to the non-shooter (and novice shooters).  This entry is a companion piece to the others in my gun series, particularly as it applies to the AR-15.  What it isn't is legal advice.  Always practice proper gun safety and know the laws in your area regarding protecting yourself with a firearm.  

It's 3:30 a.m. and you're fast asleep in your bed with your model wife, when you're awakened by what's definitely the sound of your front door being crashed in.  You're walking back to your car, after an amazing dinner out with your model wife, when you're confronted by three men, one holding a gun.  In both instances, you've made your attackers aware you have a gun, and they haven't run off.  Frequently, that's all it takes to stop an attacker, but not in these cases.  You're being forced to use your firearm for defensive use.  What are some of the things you need to consider?

Shot Placement
Where are you going to aim your gun, when you pull the trigger?  Maybe you want to avoid killing your attacker, so you'll aim for their leg.  Or you want to end the confrontation by putting a bullet in your attacker's head.  Before you answer, let me tell you what your body's doing in the moment before you pull the trigger.  Under such a life or death situation, your body is pumping a shitload of adrenalin into your system.  Adrenaline is an amazing substance and assists with energy, rapid decision making, and other critical activities during a life or death situation.  At this moment, your fine motor skills are completely destroyed and you have tunnel vision.  Unless you're in Delta, the right answer to the question you'll aim for center mass.  Attempting to hit a specific part of your attacker will result in missing it, so you aim for the largest portion of your attacker's body, the torso.  

Stopping Power - It's All About Trauma
You've fired a controlled pair of rounds into the attacker's chest, but it hasn't phased them.  They're continuing their attack and now, you're panicking.  Two more rounds haven't had any more impact on the bad guy than the first two.  This scenario isn't uncommon, believe it or not.  When a bad guy is shot by a handgun in the movies, they mostly drop dead on the spot.  However that rarely happens in real life.  Remember the adrenaline pumping through your body?  It's happening to the bad guy too and acting to suppress the pain from being shot; there may be additional substances coursing through their body further assisting in that action.  There have been studies of shooting victims, where a large portion reported not even being aware they were shot until someone pointed it out.  

In order to stop an attacker with your gun, one of three things must happen.  Sufficient trauma must be done to their body to make it stop working.  The "electrics" or "hydraulics" must be rendered inoperable.  This of course, assumes the attacker didn't run away when the bullets began to fly his way.  

"Electrics" refer to the brain sending signals to the rest of the body.  A successful head shot will stop those signals and end the fight immediately.  "Hydraulics" refer to blood being pumped by the heart and a direct hit will also end the fight rather quickly.  Again, very difficult shots to make under pressure.

That leaves us with trauma.  How much trauma is required and where?  How does a bullet create trauma?  As I mentioned, my example of the bad guy continuing their attack even after being hit by four rounds is real.  There have been numerous documented (and recorded) instances of people being killed by attackers full of 9mm hollow point ammo in their chest.  The attackers mostly died, after the fact, but in the fight, their body didn't tell them they were dead.  

I'll start with how a bullet creates trauma.  When a bullet hits a human, it creates a permanent wound channel similar in size to the bullet's diameter.  However, there's also a shock wave created by the bullet which results in a temporary wound channel.  The size of this trauma depends on bullet type and energy delivered.  Ammunition manufacturers develop their defense products to maximize both of these via a bullet design with a hollow point, which mushrooms as it travels within the target.  Under ideal circumstances, a hollow point bullet can expand to twice its diameter.  Their goal is to put as much of the round's muzzle energy to use creating trauma as possible and penetrate 12" in ballistic gelatin.  

Hollow point bullets after expansion

In the case of rifle ammunition, these wound channels are more dependent on muzzle energy bullet design.  Some rounds, such as 556 NATO will tumble through the body, creating a massive wound channel.  You may notice rifle ammo utilizing hollow point bullets, but that's solely for improved accuracy; they don't expand. 

Firing rounds into ballistic gelatin is a standard practice of measuring these cavities.

Simulated wound cavities with various handgun rounds

Simulated wound cavity with 556 NATO ammo

With exceptions of head shots or a lucky kneecap shot, most handgun rounds don't create sufficient trauma to guarantee an immediate cessation of an attack.  However, by virtue of the energy it delivers, a single rifle round will literally destroy the part of the body where it hits, often rendering the attacker's body inoperable.  The picture above illustrates this perfectly.  In some cases, the lack of power of something like a 9mm can be overcome with the sheer volume of fire from modern pistols, which can hold 19 rounds or more.  

Ballistic Performance Data for Various Cartridges

Cartridge and Gun Choice

Returning to your situation, did you choose wisely, when you bought your carry gun?  When deciding on what cartridge and gun combination to rest your life on, always choose the most powerful (creates the most trauma) option that fits within the form factor as dictated by your circumstances.  Your choice during the summer, when concealing a large gun is almost impossible, will be different than what you choose for winter, when almost any gun will disappear under a heavy coat.  Obviously, concealment isn't relevant for home defense use.  

There are also other consideration that come into play with specific cartridges.  For example, going down the list, we can immediately cross off 7.62x51 and 44 Magnum as viable defensive cartridges.  They're so brutal and you'd regret using either as a home defense gun due to how loud they are as well as the muzzle flash.  Certain cartridges were optimized for specific minimum barrel lengths.  556 NATO requires at least a 12" barrel in order to stabilize the bullet, but its performance suffers in anything under 14.5", so you're stuck with a long gun (for home defense, obviously).   It's also particularly loud, so a suppressor is almost mandatory, making the gun even longer.  I own a 556 gun with a 10" barrel and it's a certified fire breather, sounding like the god of thunder when I shoot it.  However, 300 Blackout was designed to be shot through an 8" barrel, which makes for a smaller package as a home defense gun.  

Let's not forget safety.  Even the weakest handgun rounds will over penetrate through walls like they weren't even there, which can endanger others in the home or even the neighbors.  The most extreme example happened with a friend who was shot with a 22 Long Rifle (100 ft. lbs.) through a two inch thick oak door!  Bullets from 556 and 300 Blackout aren't very good at penetrating sheetrock (walls) and tend to stay in the room they're fired in.

Ultimately, the 556 NATO definitely represents the most potent, safest home defense round, when packaged in an AR-15.  The same can be said if you carry a gun in your vehicle for emergencies.  It will end any bad guy or mob's aggression in a hurry.

My own choices are 38 Super for personal defense and 300 Blackout as a home defense round. My logic is what I lose in performance versus the 556, I gain in the smaller form factor and not blowing out my hearing (even with a silencer, 556 is still loud indoors).  

By no means are my choices the best for everyone.  There are any number of combinations and calibers that will do the job.  There are many that have a 9mm pistol for everything and that's fine. 

This entry is part of my "Gun Series" that focuses on providing insight into the gun debate and gun violence.  You can find the other entries in the series HERE.  

About the author: Sean R is a recovering conservative who owns a consulting firm specializing in strategic marketing.  He's been a competitive shooter since the early 90's and holds a High Master classification in PPC and a Master classification in USPSA.  As an instructor, he taught courses in gun safety and competition.  He lives in Raleigh, North Carolina with his overly vocal dog, Sadie.