Responding to Sunday's massacre in Orlando, the perpetrator of which used a Sig Sauer MCX rifle as well as a Glock 17 pistol, USA Today's editorial board says "assault-style weapons" are "the weapon[s] of choice of people intent on mayhem." Washington Post blogger Christopher Ingraham agrees. So do CNN, ABC News, The Globe and Mail, the Daily Mail, The Telegraph, The Australian, The Japan Times, and International Business Times.

Yet according to a Mother Jones tally of mass shootings since 1982, which includes "seemingly indiscriminate rampages in public places resulting in four or more victims killed," the vast majority of guns used in these attacks (83 percent) do not qualify as "assault weapons," an arbitrary category defined by military-style features such as folding stocks, pistol grips, and flash suppressors. Handguns were far more common, accounting for two-thirds of the weapons. If anything, handguns are the "weapons of choice" for mass shootings (as they are for other types of gun violence).

Where did all of these news outlets get the idea that "assault weapons" are the most common type of firearm used in mass shootings? It does look like such guns became more popular with mass shooters in recent years. When Mother Jones first published its database, it covered 1982 through 2012, and "assault weapons" accounted for 20 of the 143 guns used by mass shooters, or 14 percent. Mother Jones counts 19 additional incidents since then (including the Orlando nightclub attack), involving 36 weapons, of which 10, or 28 percent, were identified as "assault weapons." So this category was twice as common during the last three and a half years as it was during the previous three decades, a change that presumably reflects the general rise in the popularity of military-style rifles as well as their specific appeal to mass murderers.

This meme regarding so-called assault weapons dates back at least to 1985, when California Assemblyman Art Agnos, promoting the first state ban on such guns, described them as "'the weapons of choice' of drug dealers and some street gangs," as the Los Angeles Times put it. That was not true either. According to a 2004 report commissioned by the National Institute of Justice, assault weapons "were used in only a small fraction of gun crimes prior to [the lapsed 1994 federal ban]: about 2% according to most studies and no more than 8%."

Other "assault weapon" prohibitionists nevertheless echoed Agnos. The Nexis newspaper database counts more than 1,000 references to "assault weapons" as "weapons of choice" since 1985. Maybe all that rhetorical excess has something to do with the rise in the popularity of military-style guns among mass shooters. But keep in mind that mass shootings account for a tiny percentage of gun homicides and an even smaller percentage of gun-related deaths, two-thirds of which are suicides. In all of these categories (and in self-defense too), handguns are by far the most popular sort of firearm.

Does it matter whether mass shooters use "assault weapons" rather than another type of gun without the bells and whistles that offend politicians? USA Today thinks it does. Saying Congress should "ban assault weapons now," the paper says "such weapons are accurate and quick, firing with just the twitch of a finger." That last feature, of course, characterizes pretty much every gun ever invented. Rate of fire has nothing to do with the definition of "assault weapons," which fire no faster than hunting rifles, semi-automatic pistols, or revolvers. Nor are "assault weapons" distinguished by their accuracy, muzzle energy, or the ability to accept detachable magazines (a feature shared by many guns that are not considered "assault weapons"). Under the renewed "assault weapon" ban for which Hillary Clinton and other Democrats are clamoring, a rifle with a detachable magazine is prohibited if it has one or more of these "military characteristics": a pistol grip or forward grip, a grenade launcher or rocket launcher, a barrel shroud, a threaded barrel, or a folding, telescoping, or detachable stock.

Like USA Today, the Post's Ingraham mentions that "assault weapons" are "capable of firing many rounds of ammunition in a relatively short period of time" and even claims that "compared to other firearms, assault-style rifles make it fairly easy to kill or injure many people within a short period of time." But he never explains which special features make "assault weapons" uniquely suited to mass murder—possibly because there is no good explanation.