About the AR-15

Sam Harris has blogged about his views on gun control, personal protection, and the NRA.

I’ll start by mentioning my own background and biases. I’ve spent the last year of my life in either Lower Manhattan or London, and the four years before that on the North Side of Chicago, all of which either have or had handgun bans, and are effectively devoid of any above-ground gun culture. Unlike Mr. Harris, I’m not a public figure, and I haven’t felt unsafe going about my daily routines in nearly a decade. I work an upper middle-class job, do my bit to destroy the planet, and I don’t receive death threats. I would also not classify myself as a member of the “liberal elite,” if only because “elite” implies that your opinion on the substantive political issues of the day carries some weight with decision-makers. Mine does not.

All that said, I grew up in the distant suburbs of the Midwest, and know quite a few gun owners, NRA members, hunters, and hobbyists (for my purposes, people who build their own firearms). I’m also in favor of both strict and intelligent gun control, particularly when it comes to semiautomatic rifles.

I’ll also state flat out that I believe the job of the military is not to “defend democracy,” “spread freedom,” “oppress civilians,” or even “take over countries.” Those are all political goals, and they are handled by politicians of one stripe or another. The job of a military is to kill people and break things, ostensibly to make politicians’ goals easier to attain (hopefully, the politicians prefer “defending democracy,” to “taking over countries”).

For this discussion, I want to review the errors of perspective and fact when it comes to the AR-15. Mr. Harris obliquely referenced the rifle that the Adam Lanza used to murder children and schoolteachers, and specifically discussed both the ammunition used and the presence of other weapons. These claims are what I’m going to address here:

1. The AR-15 (or at least semi-automatic rifles) are not and cannot be designed to kill people as quickly as possible, and anyone who thinks so is a naif
2. The ammunition used by the AR-15 is not nearly so bad as it’s made out to be
3. A hunting rifle would be just as bad

Designed To Kill People

While I disagreed with a whole lot of what Mr. Harris had to say, this is the bit that caused me to take a second, more critical look at the whole thing:

Consider the sneering response of the New York Times editorial page to Wayne LaPierre, the NRA vice president, after he suggested that we station a police officer at every school in the country:

His solution to the proliferation of guns, including semiautomatic rifles designed to kill people as quickly as possible, is to put more guns in more places. Mr. LaPierre would put a police officer in every school and compel teachers and principals to become armed guards… Mr. LaPierre said the Newtown killing spree “might” have been averted if the killer had been confronted by an armed security guard. It’s far more likely that there would have been a dead armed security guard—just as there would have been even more carnage if civilians had started firing weapons in the Aurora movie theater.

The phrase “designed to kill people as quickly as possible” should tell us everything we need to know about the author’s grasp of the issue.

What Mr. Harris is suggesting is fairly obvious: anyone who uses phrases like “designed to kill people as quickly as possible” does not know what they’re talking about. The editorial in question was discussing (quite obviously) the AR-15 rifle used by Adam Lanza to murder children, and we know quite a bit about that rifle, because it’s a semi-automatic version of the M-16. Now, I believe I can infer that Mr. Harris was thinking that there is no way that a semi-automatic rifle could be “designed to kill people as quickly as possible,” because it is a semi-automatic rifle. I’ll discuss this in a bit more detail later, but for now, think of it this way: Harris had his cheap shot, as it were. This is mine.

As it turns out, the original designer of the AR-15, working at a company called Armalite, had an earlier rifle called the AR-10, which it pitched to the military after the Korean War as a replacement for the M-1 rifle (the one they used in World War II). Armalite was using a screwy mix of metals at the back of the AR-10’s barrel (the part that is next to your face), and one of them blew up while the military was testing it, so the AR-10 lost a competition to what turned into the M14 (the wood-stocked rifle that honor guards march around with and twirl during drills). It’s worth noting that the AR-10 also fired the .308 Winchester bullets that the military was using (more on that later).

Armalite redesigned the rifle to fire smaller .223 caliber bullets, stopped using screwy metals in the barrel, and called the result the AR-15. Unfortunately they already lost the contract and had a bad reputation to go with it (their last rifle blew up), so they sold the plans to Colt. Colt, in turn, pitched the AR-15 to the military, and after using the South Vietnamese Army as a guinea pig, then-Secretary of Defense McNamara bought a hundred thousand of them. The rest is a scene from Platoon.

This means the AR-15 was definitely “designed to kill people as quickly as possible,” because it was designed for the infantry, and that is what the infantry does.

Acrobatic Ammunition

The next bit worth dealing with, which actually occurs earlier in Harris’ text, discusses the ammunition intended to be used by these types of rifles.

These bullets also tend to tumble and fragment in the body, which makes them more lethal. However, one cannot say in every case that an assault rifle in the wrong hands is a greater threat to innocent life than a handgun. Rifle rounds travel at such high velocity that they sometimes pass through a person’s body before tumbling or fragmenting—doing less damage than one would expect from a handgun round. Conversely, these bullets are so light and frangible that they are sometimes stopped by barriers such as doors and wallboard.

Before continuing, I think it’s worth talking a bit about the sizes of the ammunition that is being talked about. The .30-06 round (the big cartridge on the right in the sidebar image) was the ammunition used by the semi-automatic M-1 rifle, which is what the infantry carried in World War II. The .308 Winchester round (in the center), was used by the M-14 rifle, which replaced the M-1, and 5.56mm NATO round (on the left) is what’s used by the AR-15/M-16.

One question when looking at this is “why did the military choose progressively smaller and smaller bullets?” Why did it trade in a .30-06 rifle for (effectively) a .22? There’s nearly 30 years of research behind that decision, which began (at least) with the Army looking at the effects of .22 caliber bullets when they hit people, in 1930. The Army followed that up after World War II with a lot of studies and reviews on how the infantry in World War II (and Korea) actually fought, how deadly rifles of different calibers could be, and yes, how the bullets behaved.

To cover the history briefly, a review of battle reports from Europe showed that only 15-20% of infantrymen actually fired their rifles at enemy soldiers, but machine gunners tended to do so more often. That, combined with the results of other studies convinced the Army that they should issue every soldier a rifle with a switch which would turn it into a machine gun. Unfortunately for the Army, while an average soldier can carry a .30-06 rifle, a .30 caliber machine gun is another story altogether. So the Army started a competition, and ended up picking the M-14, which fired the shorter (but similarly sized) .308 Winchester round. They picked the M-14 because it could be fired like a machine gun more effectively than the M-1.

In general, it can be stated that if the combined weight of rifle and ammunition is fixed at 15 lbs., a man carrying the Cal. .21 rifle would have an expectation of killing about 2-1/2 times as many targets as with the M-1 rifle.An Effectiveness Study of the Infantry Rifle, 1952

While this was going on, the Army was also taking another look at the smaller .22 caliber rifles. This time, they were looking at how likely it was to kill someone at various ranges when using smaller caliber bullets. The math runs roughly like this: if a .22 is 25% less likely to kill someone as a .30-06, but you can carry twice as much ammo, then you can kill more people with a .22 than you can with a .30-06. The study complained they didn’t have enough ammunition to do a detailed study of the wounds that smaller bullets created, and it took another five years for someone to put this together with the report from 1930 and do the work.

Eventually, however, the relevant experiments about wounding were conducted, and what they came up with were diagrams like those below.

To start, the rifles and cartridges that the U.S. had been using (both the M-14 and the M-1) essentially ram right through their victims:

In the diagram above, the “Permanent Cavity” means the pieces of a person that are burned, compressed, or otherwise destroyed by the bullet. In other words, it means the bits that will have to grow back. The “Temporary Cavity” refers to the bits of a person that are mushed out of the way by the force of the bullet hitting, but not actually destroyed.

If we assume that an average American male’s chest size is still 40 inches around, and if we pull a number out of our asses and assume a very generous depth ratio of 0.71 (a man’s chest is 71% as deep as it is wide), the average American chest is going to be 11.6 inches deep, or about 29cm, which I’ve marked with the red line on the diagram. With those numbers, the bullet fired by an M-14 is, for lack of a better term, designed to blow out your back.

Contrast that with damage from a full-metal jacket round that the AR-15/M-16 was designed to fire:

…While a little bullet, being it has a low mass, it senses an instability situation faster and reacts much faster… this is what makes a little bullet pay off so much in wound ballistics.Eugene Stoner, designer of the AR-15, quoted in American Rifle: A Biography

Again, the red line on the diagram indicates the back of an average American male’s chest. In this case, almost all the damage happens inside the person—you have a very small (less than 1/4 inch) hole that hides a bloody shredded bubble, several inches across, inside the victim’s body.

On 9 June a Ranger Platoon from the 40th Infantry Regt. was given the mission of ambushing an estimated VC Company. [Five VC were killed:]

1. Back wound, which caused the thoracic cavity to explode.
2. Stomach wound, which caused the abdominal cavity to explode.
3. Buttock wound, which destroyed all tissue of both buttocks.
4. Chest wound from right to left; destroyed the thoracic cavity.
5. Heel wound; the projectile entered the bottom of the right foot causing the leg to split from the foot to the hip.

These deaths were inflicted by the AR-15 and all were instantaneous except the buttock wound. He lived approximately five minutes.

ARPA report, cited in American Rifle: A Biography

So why is the smaller bullet so much more destructive? One of the things discovered during the 1930 study was what happens when you move the center of gravity towards the back of the bullet. The back of the bullet wants to keep moving after the front has slowed down. If this happens on a bullet that was already spinning, the back will try to cartwheel over the front.

Unfortunately for the victim, the front of the bullet doesn’t slow down quickly enough to cause tumbling until it’s already inside, so the bullet will try to cartwheel over itself inside their body. If the bullet is travelling fast enough when it hits, then the shearing force on the bullet trying to cartwheel through a person is stronger than the strength of the metal in the bullet, and the bullet will tear itself apart inside a person’s body.

To get a better understanding of this, imagine the deep shock you feel when you belly-flop into a pool. Now imagine how bad it would be if you belly-flopped at Mach 3: you would splatter into little pieces when you hit.

A thinner bullet means less metal, means less strength. So, by using thinner bullets and making them go faster, the bullet actually does a lot more damage than a bigger bullet. That’s also why the (shiny) casing around the 5.56mm round is nearly as big as the one on the much larger .308 Winchester—there’s more explosives packed into it, which makes the bullet travel faster when the gun goes off. Fast enough to make the bullet come apart if it hits something less than 300 feet away.

You shouldn’t be surprised to learn that Army studies also found that when there was an infantry battle, the soldiers on either side were usually less than 300 feet away from each other.

I think we can cut to the chase: the full-metal jacket ammunition designed for use with an AR-15 was intended to tumble and fragment inside anyone unfortunate to be shot with one, and the military would not have switched to the significantly smaller M-16 without knowing in advance that it was an all-around deadlier weapon than the rifles it was replacing. It’s supposed to hit a person standing less than 300 feet away at something like Mach 3, and splatter into little pieces.

Does this mean full-metal jacket ammunition fired from AR-15 will always tumble and fragment? No, of course not. Nothing works as advertised all the time. But that is absolutely what it is supposed to do, and the fact that ammunition sometimes fails to be as vicious as it’s designers hoped doesn’t mean a damned thing.

Strictly for comparison, here’s what a hollow-point bullet fired from a .357 Magnum does:

Obviously, you’d rather be shot by none of these, but it’s worth noting that even a hollow-point from a .357 Magnum is tame compared to the round an AR-15 was designed to fire.

Not All Rifles Are Equal

Lastly (for this article), Harris believes rifles are only really necessary beyond 60 feet, and it doesn’t really matter what kind of rifle you are using:

Nor is anyone advocating that we deprive hunters of their rifles. And yet any rifle suitable for killing deer is just the sort of gun that will allow even an unskilled shooter to wreak absolute havoc upon innocent men, women, and children at a range of several hundred yards. There is, in fact, no marksman on earth who can shoot a handgun as accurately at distance as you would be able to shoot a rifle fitted with a scope after a few hours of practice. This difference in accuracy between short and long guns must be experienced to be understood. Having understood it, you will in no way be consoled to learn that a madman ensconced on the rooftop of a nearby building is armed merely with a “hunting rifle” that is legal in all 50 states.

What Harris is doing here is muddling the qualitative difference between rifles by contrasting all rifles with pistols. It’s a slick debating trick he uses to claim that a “hunting rifle” (which no one is seriously considering banning) is just as lethal as an “assault rifle”.

This is, of course, not even wrong, and I’m going to refer back to the military to make the point. The evolution of military weapons over the last three centuries has gone something like this:

Muzzle-loaders

The first rifles, where you put the bullet in the front and tamp it down.

Breech-loaders

A rifle where you open the back of the barrel, put the bullet in, then close it.

Lever-action

The western-style breech-loader rifles that let you load more than one cartridge at a time, and get a new round ready to fire by working the trigger-guard.

Bolt-action

A rifle which lets you reload by working a bolt at the back of the barrel. A bolt-action rifle means you do not have to change the position of the rifle to get a new round ready to fire (which you do need to do with a lever-action rifle)

Semi-automatic

A rifle with a magazine that uses the explosion that fires the bullet to get the next round ready to fire automatically.

Fully Automatic

A machine gun. In addition to getting a new round ready to fire, it also throws the spring-loaded firing pin, which springs back and then fires the round it just got ready.

Burstable

A middle-ground between the fully- and the semi-automatic rifle modes, this mode fires three rounds like a machine gun, then stops.

Along with the changes in how a rifle loads the next bullet came increases in capacity, from 1 bullet at a time to 30 (or more). There’s a reason for all this: the faster a soldier can accurately fire bullets at people, the more people they can kill. And yes, the Army did a study on it.

It doesn’t even take a lot of imagination to see where the point of diminishing returns was reached on the rate-of-fire graph—they removed the fully-automatic mode from the M-16 and replaced it with the burstable mode, because at 14.2 rounds a second, you can only fire an M-16 for 2 seconds (and not very accurately) before you need to reload. Reloading takes at least a few seconds to do, and so it reduces your long-term rate-of-fire.

In other words, the U.S. military, in the quest to kill people as efficiently as possible, has actually removed the “machine gun” feature of the M-16 in favor of something that works (in practice) much like a semi-automatic sawed-off shotgun. This too, has it’s roots in an Army study: if a soldier can fire four bullets into a 20 inch circle drawn around a person’s chest, chances are better than average that they’ll hit something the victim needs in order to live.

Bluntly, claiming there is no difference between an AR-15 and a bolt-action hunting rifle is nonsense. If you actually believe that, you would advocate the military issue the same M1903 bolt-action rifles they were using in World War I. After all, what’s the difference?

An Applied Science

Returning to one of my starting assumptions, that the job of any military is to kill people and break things, it should be evident by now that the more technologically advanced a country is, the more its military will come to resemble the results of applied science. Specifically, the results of science in the service of killing people and breaking things.

When it comes to infantry warfare, you want to make it as easy as possible for your soldiers to kill a lot of the other guy’s soldiers. In other words, you take a data-driven approach to small arms design, and you engineer your weapons in order to make it easier for your soldiers to kill people—which is exactly what the U.S. military did, studying battles and tactics across three continents in an attempt to introduce the same sorts of science behind mechanized and nuclear warfare into the infantry.

It’s not even unreasonable to say that the AR-15 was the result of a peacetime infantryman’s version of the Manhattan Project: reviews of every battle fought in World War II and Korea, physics calculations of the ballistics of smaller caliber weapons, statistical analyses of carrying and killing ability of different rifles, and horrific field-testing. The end result was an infantry weapon with serious effort, research, and engineering invested in making it more vicious and more deadly in the hands of an untrained, unskilled draftee than anything which came before it.

Given that, I don’t think it’s possible to justify civilian ownership of them, just as it’s impossible to justify civilian ownership of tanks, artillery pieces, and weapons of mass destruction.