More Than Half of Mass Shooters Used Assault Weapons and High-Capacity Magazines

Congress considers banning weapons that have caused carnage in shopping malls, schools, and city streets.

Fight disinformation: Sign up for the free Mother Jones Daily newsletter and follow the news that matters.


The political fortunes of the Assault Weapons Ban of 2013 have looked dim from the start. But as Congress considers the new legislation put forth by Sen. Dianne Feinstein (D-Calif.), one thing is clear: If it were to pass, the bill would outlaw highly lethal firearms that dozens of mass shooters in the United States have used to unleash carnage.

More than half of the killers we studied in our investigation of 62 mass shootings over the last three decades possessed weapons that would be banned by Feinstein’s bill, including various semi-automatic rifles, guns with military features, and handguns using magazines with more than 10 rounds. The damage these weapons can cause has been on grim display since last summer, from Aurora to Milwaukee to Minneapolis to Newtown, where attacks carried out with them left a total of 118 people injured and dead.

“They got the most shots,” said a Chicago teenager who prefers high-capacity magazines. “You can shoot forever.”

Ultimately, “assault weapon” and “high-capacity magazine” are political terms—there is no official or widely accepted definition for either, and different legislation has treated them differently. Feinstein’s new bill seeks to improve upon the 1994 ban she authored, which expired in 2004; gun manufacturers easily sidestepped that law by making superficial modifications to their weapons.

The new legislation aims to outlaw weapons that let a shooter fire a large number of bullets quickly without having to reload. Law enforcement officials we consulted generally considered that to be a reasonable approach for distinguishing between firearms used for sport or self-defense and military-style weapons designed to maximize body counts.

Using the parameters of the new bill, we dove deeper into the data on mass shootings that we first began gathering in July after the slaughter at the movie theater in Aurora, Colorado. We dug up additional specific details on the perpetrators’ guns and ammunition devices (often elusive, particularly with older cases). In our initial analysis we had used broader criteria for “assault weapons,” including some modified shotguns and bolt-action rifles; now, our more detailed chart and data set use four categories of firearms: semi-automatic handguns, rifles, revolvers, and shotguns. Across those four categories, we account for assault weapons and guns using high-capacity magazines that would be specifically outlawed by the new legislation. The data includes all guns recovered at the scene in each case, though not all of them were used in the crimes. Using this criteria we found:

  • 42 guns with high-capacity magazines, across 31 mass-shooting cases
  • 20 assault weapons, across 14 mass-shooting cases
  • 33 cases involving assault weapons or high-capacity magazines (or both)

A total of 48 of these weapons (accounting for the overlap between the two categories) would be illegal under the new legislation.*

Feinstein’s Assault Weapons Ban of 2013 isn’t just about mass shootings, of course. By far the most common weapons used in these cases are semi-automatic handguns—the type of weapon also at the heart of the daily gun violence plaguing American communities. Banning high-capacity magazines may be especially key with regard to these guns, not only because they’re popular among mass shooters, but also because they tend to increase casualties in street violence, as a veteran ATF agent explained to us in a recent interview.

The devices have appeal on the streets. A Chicago high school student recently described his preference for 30-round magazines to a reporter for This American Life: “They got the most shots. You can shoot forever. Let out 15. Run back to where you going. Somebody else come out and let out five more. There you go.”


Don’t miss our yearlong investigation into gun laws and mass shootings. And click here for the full view of the below data set.

Correction: Due to a labeling mistake, the chart at the top originally showed a total of 62 weapons rather than 48.

WE'LL BE BLUNT.

We have a considerable $390,000 gap in our online fundraising budget that we have to close by June 30. There is no wiggle room, we've already cut everything we can, and we urgently need more readers to pitch in—especially from this specific blurb you're reading right now.

We'll also be quite transparent and level-headed with you about this.

In "News Never Pays," our fearless CEO, Monika Bauerlein, connects the dots on several concerning media trends that, taken together, expose the fallacy behind the tragic state of journalism right now: That the marketplace will take care of providing the free and independent press citizens in a democracy need, and the Next New Thing to invest millions in will fix the problem. Bottom line: Journalism that serves the people needs the support of the people. That's the Next New Thing.

And it's what MoJo and our community of readers have been doing for 47 years now.

But staying afloat is harder than ever.

In "This Is Not a Crisis. It's The New Normal," we explain, as matter-of-factly as we can, what exactly our finances look like, why this moment is particularly urgent, and how we can best communicate that without screaming OMG PLEASE HELP over and over. We also touch on our history and how our nonprofit model makes Mother Jones different than most of the news out there: Letting us go deep, focus on underreported beats, and bring unique perspectives to the day's news.

You're here for reporting like that, not fundraising, but one cannot exist without the other, and it's vitally important that we hit our intimidating $390,000 number in online donations by June 30.

And we hope you might consider pitching in before moving on to whatever it is you're about to do next. It's going to be a nail-biter, and we really need to see donations from this specific ask coming in strong if we're going to get there.

payment methods

WE'LL BE BLUNT.

We have a considerable $390,000 gap in our online fundraising budget that we have to close by June 30. There is no wiggle room, we've already cut everything we can, and we urgently need more readers to pitch in—especially from this specific blurb you're reading right now.

We'll also be quite transparent and level-headed with you about this.

In "News Never Pays," our fearless CEO, Monika Bauerlein, connects the dots on several concerning media trends that, taken together, expose the fallacy behind the tragic state of journalism right now: That the marketplace will take care of providing the free and independent press citizens in a democracy need, and the Next New Thing to invest millions in will fix the problem. Bottom line: Journalism that serves the people needs the support of the people. That's the Next New Thing.

And it's what MoJo and our community of readers have been doing for 47 years now.

But staying afloat is harder than ever.

In "This Is Not a Crisis. It's The New Normal," we explain, as matter-of-factly as we can, what exactly our finances look like, why this moment is particularly urgent, and how we can best communicate that without screaming OMG PLEASE HELP over and over. We also touch on our history and how our nonprofit model makes Mother Jones different than most of the news out there: Letting us go deep, focus on underreported beats, and bring unique perspectives to the day's news.

You're here for reporting like that, not fundraising, but one cannot exist without the other, and it's vitally important that we hit our intimidating $390,000 number in online donations by June 30.

And we hope you might consider pitching in before moving on to whatever it is you're about to do next. It's going to be a nail-biter, and we really need to see donations from this specific ask coming in strong if we're going to get there.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate