According to Broward County Sheriff Scott Israel, an AR-15 rifle was believed to be used in a school shooting Wednesday at Marjory Stoneman Douglas High School in Parkland, Florida, in which at least 17 people were killed. The AR-15 is the same weapon used by Adam Lanza, who killed 26 people, 20 of them children, at Sandy Hook Elementary School in 2012. After the Sandy Hook shooting, Justin Peters wrote that “the AR-15 is very good at one thing: engaging the enemy at a rapid rate of fire.” The original piece is reprinted below.

On Dec. 24, in Webster, New York, an ex-con named William Spengler set fire to his house and then shot and killed two responding firefighters before taking his own life. He shot them with a Bushmaster AR-15-style semi-automatic rifle—the same weapon that Adam Lanza used 10 days earlier when he shot and killed 26 people at Sandy Hook Elementary. James Holmes used an AR-15-style rifle with a detachable 100-round magazine this past summer when he shot up a movie theater in Colorado. (Though the AR-15 is a specific model of rifle made by Colt, the term has come to generically refer to the many other rifles built to similar specifications.)

Three makes a trend, as we all know, and many people have reacted by suggesting that the federal government should ban the AR-15 and other so-called assault weapons. Gun advocates have responded with exasperation, saying that, despite appearances, AR-15-style rifles are no more dangerous than any other gun. In a piece today on humanevents.com titled “The AR-15: The Gun Liberals Love to Hate,” NRA president David Keene blasted those critics who “neither understand the nature of the firearms they would ban, their popularity or legitimate uses.” Keene noted there are several valid, non-murderous uses for rifles like the AR-15—among them recreational target shooting, hunting, and home defense—and argued that law-abiding firearms owners shouldn’t be penalized because of homicidal loners who use semi-automatics like the AR-15 for criminal purposes.

I generally consider myself a Second Amendment supporter, and I haven’t yet decided where I stand on post-Newtown gun control. I would own a gun if New York City laws didn’t make it extremely difficult to do so. But I nevertheless find Keene’s arguments disingenuous. It’s odd to cite hunting and home defense as reasons to keep selling a rifle that’s not particularly well suited, and definitely not necessary, for either. Bolt-action rifles and shotguns can also be used for hunting and home defense. Unfortunately, those guns aren’t particularly lucrative for gunmakers. The lobby’s fervent defense of military-style semi-automatic weapons like the AR-15 seems motivated primarily by a desire to protect the profits in the rapidly growing “modern sporting rifle” segment of the industry.

The AR-15 was designed in 1957 at the behest of the U.S. Army, which asked Armalite to come up with a “high-velocity, full and semi auto fire, 20 shot magazine, 6lbs loaded, able to penetrate both sides of a standard Army helmet at 500 meters rifle,” according to ar15.com. When it entered Army service in the 1960s, it was renamed the M16, in accordance with the Army Nomenclature System. “AR-15” came to refer to the rifle’s semi-automatic civilian equivalent. From 1994 to 2004, AR-15-style rifles were subject to the now-expired Federal Assault Weapons Ban. Since then, the rifle and others like it have become tremendously popular. Last month, I estimated that upward of 3.5 million AR-15-style rifles currently exist in the United States. People like the rifle because it is modular and thus customizable (one article calls the AR-15 “perhaps the most flexible firearm ever developed; in seconds, a carbine can be switched over to a long-range rifle by swapping upper receivers”), because it is easy to shoot, and because carrying it around makes you look like a badass.

But the AR-15 is not ideal for the hunting and home-defense uses that the NRA’s Keene cited today. Though it can be used for hunting, the AR-15 isn’t really a hunting rifle. Its standard .223 caliber ammunition doesn’t offer much stopping power for anything other than small game. Hunters themselves find the rifle controversial, with some arguing AR-15-style rifles empower sloppy, “spray and pray” hunters to waste ammunition. (The official Bushmaster XM15 manual lists the maximum effective rate of fire at 45 rounds per minute.) As one hunter put it in the comments section of an article on americanhunter.org, “I served in the military and the M16A2/M4 was the weapon I used for 20 years. It is first and foremost designed as an assault weapon platform, no matter what the spin. A hunter does not need a semi-automatic rifle to hunt, if he does he sucks, and should go play video games. I see more men running around the bush all cammo’d up with assault vests and face paint with tricked out AR’s. These are not hunters but wannabe weekend warriors.”

In terms of repelling a home invasion—which is what most people mean when they talk about home defense—an AR-15-style rifle is probably less useful than a handgun. The AR-15 is a long gun, and can be tough to maneuver in tight quarters. When you shoot it, it’ll overpenetrate—sending bullets through the walls of your house and possibly into the walls of your neighbor’s house—unless you purchase the sort of ammunition that fragments on impact. (This is true for other guns, as well, but, again, the thing with the AR-15 is that it lets you fire more rounds faster.)

AR-15–style rifles are very useful, however, if what you’re trying to do is sell guns. In a recent Forbes article, Abram Brown reported that “gun ownership is at a near 20-year high, generating $4 billion in commercial gun and ammunition sales.” But that money’s not coming from selling shotguns and bolt-action rifles to pheasant hunters. In its 2011 annual report, Smith & Wesson Holding Corporation announced that bolt-action hunting rifles accounted for 6.6 percent of its net sales in 2011 (down from 2010 and 2009), while modern sporting rifles (like AR-15-style weapons) accounted for 18.2 percent of its net sales. The Freedom Group’s 2011 annual report noted that the commercial modern sporting rifle market grew at a 27 percent compound annual rate from 2007 to 2011, whereas the entire domestic long gun market only grew at a 3 percent rate.

As the NRA’s David Keene notes, a lot of people do use modern sporting rifles for target shooting and in marksmanship competitions. But the guns also appeal to another demographic that doesn’t get nearly as much press—paranoid survivalists who worry about having to fend off thieves and trespassers in the event of disaster. Online shooting message boards are rife with references to potential “SHTF scenarios,” where SHTF stands for “shit hits the fan”—governmental collapse, societal breakdown. (Adam Lanza’s mother, Nancy Lanza, has been described as “a gun-hoarding survivalist who was stockpiling weapons in preparation for an economic collapse.”) An article on ar15.com titled “The Ideal Rifle” notes that “the threats from crime, terrorism, natural disaster, and weapons of mass destruction are real. If something were to happen today, you would need to have made a decision about the rifle you would select and be prepared for such an event. So the need to select a ‘survival’ rifle is real. Selecting a single ‘ideal rifle’ is not easy. The AR-15 series of rifles comes out ahead when compared to everything else.” Depending on where you live, it’s perfectly legal to stockpile weapons to use in the event of Armageddon. But that’s a far different argument than the ones firearms advocates have been using since the Newtown shootings.

As I said, I generally think of myself as a Second Amendment supporter, and a month ago, I would’ve probably agreed with the NRA’s position. But the Newtown shooting caused me to re-examine my stance—as is, I think, fitting—and to question some of the rhetoric advocates use to defend weapons like this. In his piece at Human Events, Keene ridiculed the notion that AR-15-style rifles ought to be banned just because “a half dozen [AR-15s] out of more than three million have been misused after illegally falling into the hands of crazed killers.” But the AR-15 is very good at one thing: engaging the enemy at a rapid rate of fire. When someone like Adam Lanza uses it to take out 26 people in a matter of minutes, he’s committing a crime, but he isn’t misusing the rifle. That’s exactly what it was engineered to do.

Read more from Slate on the Orlando nightclub shooting.