When learning about firearms, it’s important to be precise. There’s a wealth of terminology and an even greater number of products on the market.
So when wondering about ammo, simply asking “what bullets do the most damage?” is a vague question.
You must qualify it for it to make sense. For example, a shotgun slug will do far more damage to a barn door than a .22 will do to a pig, yet the .22 caliber has been used in more killings than the shotgun slug.
OK, then what are we talking about here? There are only a few reasons why this conversation would be taking place.
The first is sheer curiosity. Some bullets look pretty gnarly, and naturally you would think they would do severe damage to anything they encounter.
You might wonder why all bullets aren’t made that way. Another reason this discussion might come up is to cause debate amongst friends or in political circles.
The final reason — and the one being addressed here — is if someone is trying to make an informed decision about which rounds best suit home defense or everyday carry needs.
All Bullets Can Be Lethal
Let’s start off with a little cold, hard truth that many people simply don’t like. All bullets are inherently lethal.
Even so-called “non-lethal” or “less-than-lethal” rounds have accidentally killed people.
All bullets are dangerous — in fact, even the use of blank-firing cartridges has led to deaths in some extremely rare cases.
This brings us to the next point: Despite what gun legislation opponents will tell you, no bullet is “designed for the battlefield” and inherently more dangerous than others.
Almost every caliber round has been used somewhere in a theater of war.
While there are some obscure rounds that were never used in battle, there’s honestly no round that is somehow safer than another because the military isn’t currently using it.
This brings up another point worth mentioning: Hollow points and full metal jacket rounds are inherently no different from each other at their most basic level.
They are both projectiles designed to be fired from a gun and can both kill. In fact, for those that think hollow points are somehow more deadly, the U.S. military doesn’t use hollow point ammunition in infantry units.
It uses FMJ. Again, that doesn’t mean they are more deadly. It just means that a bullet is a bullet.
The point here is that there are many misconceptions about different ammunition and the reality is that most of them are conjecture at best and outright lies at worst.
What Constitutes Damage?
When it comes to the measurement of ammunition capabilities, damage is measured in a couple of ways.
First, most rounds are measured by ballistic coefficient. Next, rounds are often judged by penetration ability.
Lastly, damage can be measured by the size of the overall hole left on the object the bullet struck.
Ballistic Coefficient
What exactly is a ballistic coefficient? In the simplest terms, a ballistic coefficient is the ability of the bullet to overcome air resistance in flight.
The better a bullet is able to overcome air resistance as it flies, the more energy it retains through flight.
The more energy the bullet retains over the course of flight, the more energy it has to deliver into the target.
While this isn’t the only thing you should be looking at in terms of judging your potential rounds for the damage they can do, it’s a good indicator that you’re on the right track.
There are other factors involved here too, like the mass of the bullet, but that is a part of the calculation for the ballistic coefficient.
So, as a general rule, the higher the ballistic coefficient number, the more damage the bullet is capable of inflicting.
It doesn’t mean it will — just that it could.
Penetration
This is also a factor that can be misleading. Like the ballistic coefficient, the penetration capability of the round deals with the potential of the round to deliver damage.
Rounds with the ability to penetrate well into the target are more capable of delivering energy into the target.
In older times, to ensure something that was shot was truly shot, manufacturers would try to load as much powder as possible into loads.
This was because some rounds that were made for handguns but that could be fired from rifles — such as the .44 Long Colt — might not actually enter into the target far enough to accomplish the intended goal.
Plus, thick layers of clothing or degrees of distance could cause some rounds to fail at truly damaging an intended target.
This is where a round’s penetration ability became important.
The powder loads were adjusted over time, along with bullet designs and materials used, to ensure a more stable flight path for the round.
This has allowed modern loads to use only enough powder to deliver the round while ensuring it's able to penetrate the target on arrival.
Now, rather than running the risk of over or under penetration, the rounds are more consistent throughout their journey.
As far as damage is concerned, this penetration ability can translate to larger cavities as the round travels farther into and even through the intended target.
But, as with the other measurements, this factor alone is not a solid judgement of what makes a round do more damage.
The .223/5.56, for example, is known for penetration ability, but there is a ton of evidence of people being shot and having rounds go right through them without them even knowing.
Penetration alone is not enough of a barometer.
Exit Wound/Wound Cavity
Another factor for measuring damage is the size of the wound cavity a round makes and the exit hole it leaves.
Some rounds deliver their energy in such a way that the force pushes through, causing a cavity to form around the bullet.
Most rounds create a cavity much larger than the round itself, so the size of the round is not a factor. What can be important is a combination of the size and other factors as well as the composition of the target.
In addition, when this occurs, it leaves an exit wound with a much larger hole than that of the entry wound.
Again, this one factor alone is not enough to judge which rounds do the most damage.
It's a combination of all factors, plus the type of gun being used and the conditions at the time of fire.
Rounds are designed to very specific standards and tolerances, and any number of factors can throw them off.
Everything from the weather to the way you hold the gun can negatively impact the ability of the round to perform optimally.
Most Damaging Rounds
So, what does the most damage then?
Which rounds have the best combination of those factors aside from the person pulling the trigger?
However, the answer is simple: It isn’t about what’s best, but rather what’s best for you.
It’s going to depend on what gun you’re using and your purpose for that gun.
Someone going to war has different needs than someone carrying for self-defense. But that said, the most popular calibers of bullets are popular for a reason.
For handguns, you can’t go wrong with a 9mm, a .40 or a .45 caliber. Based on ballistic tests, all these rounds are capable of doing more than enough damage to suit your needs.
Similarly, for rifles, the .223/5.56 rounds, .308, 7.62 x 39mm and even .300 Blackout are all equally damage-inducing depending on application.
The reality of the situation is that for modern uses, there is no one round that does more damage in all situations for all shooters.
They all do fantastic jobs depending on why you’re buying them. Like everything else, it’s situationally driven.
So get out there and find what works best for you; the exploration is the fun part.
