What's an Assault Weapon?

New survey data suggest most Americans don't know which guns are covered by the ban they support.

Last week Sen. Dianne Feinstein introduced a new, supposedly improved version of the federal "assault weapon" ban that expired in 2004. But like that earlier law, which the California Democrat also sponsored, Feinstein's bill prohibits the manufacture and sale of guns based on characteristics that have little or nothing to do with the danger they pose. 

Although arbitrary distinctions are a defining characteristic of "assault weapon" bans, recent polls indicate that most Americans support them. New survey data suggest one possible explanation: Most Americans don't know what "assault weapons" are. 

Feinstein's bill would ban "157 dangerous military-style assault weapons" by name, along with other guns that meet certain criteria. A rifle is considered an "assault weapon," for example, if it has a detachable magazine and 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. 

The New York Times reported that Feinstein's bill would "ban certain characteristics of guns that make them more lethal." But how exactly do these features—a threaded barrel, say, or a grenade or rocket launcher without grenades or rockets (both of which are banned for civilian use)—make a gun "more lethal"? The distinguishing characteristics of "assault weapons" are mainly cosmetic and have little or no functional significance in the context of mass shootings or ordinary gun crimes. 

CNN made an even bigger mistake, claiming the bill is aimed at "rifles capable of firing multiple rounds automatically." In reality, the bill has nothing to do with machine guns such as those used by the military, which fire continuously (or "automatically") when you pull the trigger and are already tightly restricted by federal law; it deals only with semiautomatics, which fire once per trigger pull. 

Perhaps we should not be too hard on CNN, since President Obama, who supports a new ban on "assault weapons," also seems to think they are machine guns, referring to them as "AK-47s" and "automatic weapons." Contrary to the impression left by such descriptions, "assault weapons" are not distinguished by their rate of fire, the number of rounds they hold, or the caliber of their ammunition. 

A Reason-Rupe Public Opinion Survey conducted this month suggests such misconceptions are common. After asking the 1,000 respondents if they thought people should be "prohibited from owning assault weapons," the survey (which is sponsored by my employer, the Reason Foundation) asked half of the sample to "describe an assault weapon." The answers are illuminating. 

About two-thirds of the respondents described "assault weapons" as guns that fire rapidly, guns that can fire a large number of rounds without reloading, guns with a lot of "power," or guns used by the military. More than a quarter described them as "machine guns," "automatics," or the equivalent (e.g., "multiple rounds with just one pull of the trigger"). 

Overall support for banning "assault weapons" was only 44 percent, considerably lower than the 60 percent or so in recent Gallup and ABC News polls. But there was majority support—53 percent and 59 percent, respectively—among people whose descriptions of "assault weapons" emphasized rate of fire (including those who mistakenly described them as machine guns) or ammunition capacity. 

One respondent said an "assault weapon" is a "weapon that is similar to the one that caused the tragedy in Newtown," referring to last month's massacre at Sandy Hook Elementary School. That horrifying event, of course, was the pretext for Feinstein's bill, although the Bushmaster rifle Adam Lanza used to murder 20 children and six adults was not covered by the old federal "assault weapon" ban or by a similar law in Connecticut. 

Feinstein has addressed that omission by adding Lanza's rifle to her list of prohibited weapons, which may seem emotionally satisfying. But since would-be mass murderers have plenty of equally effective alternatives, it is logically equivalent to banning the car Lanza drove to the school.