The AR-15 Is A Lot Like Other Rifles

Reading some of the pieces coming out from major venues such as the NY Times and The Atlantic over the weeks since the Parkland school shooting, it's struck me that we can see reporters at least trying to write factually accurate stories about the AR-15 type rifles which they clearly believe should be banned, yet not having the knowledge of the subject to allow them to put the facts they report into proper context.

For instance, a NY Times piece I saw the other day tries to make the case that AR-15 rifles are practically the same as the M-16 rifles and M-4 carbines used by the military. It provides the following image comparing an M-16 to models of AR-15 used in various mass shootings, one assumes in order to make the point that they look rather similar.

Then it admits the very significant feature which distinguishes military long arms from their civilian counterparts (selective fire: the existence of a mode in which the rifle can fire multiple shots while the trigger is held down) but argues that this feature is not very important:

The main functional difference between the military’s M16 and M4 rifles and a civilian AR-15 is the “burst” mode on many military models, which allow three rounds to be fired with one trigger pull. Some military versions of the rifles have a full automatic feature, which fires until the trigger is released or a magazine is empty of ammunition.

But in actual American combat these technical differences are less significant than they seem. For decades the American military has trained its conventional troops to fire their M4s and M16s in the semiautomatic mode — one bullet per trigger pull — instead of on “burst” or automatic in almost all shooting situations. The weapons are more accurate this way, and thus more lethal.
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What all of this means is that the Parkland gunman, in practical terms, had the same rifle firepower as an American grunt using a standard infantry rifle in the standard way.

The article then attempts to lay out what the author believes are the important similarities between military rifles and AR-15 type civilian rifles:

Like the military’s M4s and M16s, civilian AR-15s are fed with box magazines — the standard magazine holds 30 rounds, or cartridges — that can be swapped out quickly, allowing a gunman to fire more than a hundred rounds in minutes. That is what the police described the Parkland gunman as having done. In many states, civilians can buy magazines that hold many more rounds, including 60- and 100-round versions.
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The small-caliber, high-velocity rounds used in the military rifles are identical to those sold for the civilian weapons. They have been documented inflicting grievous bone and soft-tissue wounds. Both civilian and military models of the rifle are lightweight and have very little recoil.

Now, it's true that both the AR-15 and military rifles have detachable box magazines. However, that's a trait that AR-15 type rifles have in common with virtually all other semi-automatic rifles and even with a lot of bolt action rifles. Detachable magazines are hundred year old technology. It's easier to load a magazine when it's not attached to the rifle, and it's also easier to make sure that a gun is absolutely safe if you can simply take the magazine out and then work the action to be sure that's no round in the chamber.

It's also true that many AR-15s shoot the same .223 Remington/5.56 NATO round which is used by the US military. (Not all do. One of the reasons for the huge popularity of the AR-15 platform and its big brother that AR-10 is that they are incredibly modular designs which are available in a huge variety of calibers.) However, there are lots of rifles (including bolt action and single shot shot rifles) which use the popular .223 cartridge.

Some articles, most notably a piece in The Atlantic written by a radiologist who helped treat the Parkland victims, have pointed out that the .223 round fired by most AR-15s is far more destructive than the handgun rounds typically found in homicides and suicides. This is true. While rifles are only rarely used in crimes, they pack a much greater punch than pistols do, going through body armor and causing much worse wounds.

However, not only is the .223 not unique in this respect, it's actually one of the least powerful rifle cartridges. This is actually one of the reasons why the .223 is so popular: it's easy to shoot due to its low recoil and also cheap to buy because it has less material in it. A standard 55gr .223 bullet weighs only a third as much as a .30 caliber bullet such as might be used in a .308 or .30-06 round, and the size of the brass case and amount of powder used are also proportionally smaller. This is, interestingly, one of the reasons the US military adopted the diminutive .223: It's much lighter to carry and for infantry soldiers already carrying a lot of gear, weight matters.

Checking a handgun ballistics table, the popular 9mm Luger cartridge used in many popular pistols launches a bullet with 341 foot pounds of energy as it leaves the muzzle. Compare that to a rifle ballistics table and you can see why the radiologist writing in the Atlantic was shocked when she saw .223 wounds after having only dealt with handgun wounds in the past. The .223 bullet clears the muzzle with 1291 foot pounds of energy, almost four times the energy of the 9mm Luger. However, if you compare that to common hunting rifle cartridges, they are actually all significantly more powerful: .270 Winchester 2705 ft lbs, .308 Winchester 2649 ft lbs, .30-06 Springfield 2820 ft lbs

So although the .223 is about three times higher in energy than popular handgun rounds, many standard rifle rounds are actually twice as powerful as the .223. Indeed, many states ban the use of .223 when hunting deer on the theory that it is not lethal enough to cause a humanely quick death for the animal.

This is the major problem facing any attempt to reduce gun deaths by regulating particular gun features. While certain guns catch the imagination of the public as being more dangerous than others, the ones thus singled out function often very similarly to others in many important respects.