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Assault weapons and high-capacity magazines have repeatedly been used to commit some of the worst mass shootings in modern U.S. history, and they contribute to the daily toll of gun violence in communities around the country. They are weapons of war that have no place in civilian society. Congress must enact a federal ban on assault weapons and high-capacity magazines to keep these dangerous weapons out of U.S. communities.

What is an assault weapon?

Assault weapons are semi-automatic firearms—meaning that they fire a round every time the trigger is pulled—that are capable of accepting a detachable magazine and have another military-style feature such as a pistol grip, a folding stock, or a threaded barrel. Firearm manufacturers, in response to declining sales of handguns, began selling assault rifles in the civilian market in the 1980s as part of a broader effort to create a new market for military-style guns among civilian gun owners.

What is a high-capacity magazine?

A high-capacity magazine—also referred to as a large-capacity magazine—is a device that feeds ammunition into a firearm that holds more than 10 rounds of ammunition. A gun fitted with a high-capacity magazine can fire a higher number of bullets before needing to be reloaded. Today, models exist that can hold 20, 30, 50, or 100 rounds of ammunition in a single magazine. The functionality of high-capacity magazines has advanced in recent years, with the firearms and ammunition industry designing the devices to reduce the probability that ammunition will jam while multiple rounds are rapidly fired. Magazines that accept more than 10 rounds of ammunition can be used in both long guns and handguns that accept detachable magazines.

What happens when an assault weapon with a high-capacity magazine is used in a shooting?

The use of an assault weapon equipped with a high-capacity magazine increases the likelihood that a particular shooting will have a high death and injury count. These weapons are designed to fire bullets at higher velocities than handguns, increasing the lethality of shootings perpetrated with them. An analysis of mass shootings committed from January 2009 through July 2015 found that when assault weapons or high-capacity magazines were used, 155 percent more people were shot, and 47 percent more people were killed.

What is the current federal law regarding assault weapons and high-capacity magazines?

There are currently no restrictions in federal law on the manufacture, sale, and possession of assault weapons and high-capacity magazines. In 1994, a federal ban was enacted on assault weapons and high-capacity magazines as part of the Violent Crime Control and Law Enforcement Act, but it was allowed to expire in 2004.

Do any states ban assault weapons and high-capacity magazines?

Currently, seven states and Washington, D.C. have laws banning assault weapons, while nine states and Washington, D.C. ban high-capacity magazines. Yet these state-level efforts are undermined by the lack of a strong federal law banning these weapons. In July 2019, for example, a shooter shot 15 people, killing 3, in Gilroy, California, using an assault rifle purchased in Nevada. Although this firearm was banned and unavailable for sale in California, it was easily available in Nevada, which does not have a state-level assault weapons ban.

Do bans on assault weapons and high-capacity magazines work?

A growing body of research finds that the federal assault weapons ban—though only in effect for 10 years—had a positive impact on reducing both the use of assault weapons in crimes and the numbers of firearm injuries and fatalities in mass shootings:

In 2004, the U.S. Department of Justice found that following the implementation of the ban, a number of cities and jurisdictions reported declines in the number of assault weapons recovered from crime scenes. These declines ranged from 17 percent to 72 percent.

Researchers analyzing public mass shootings from 1982 through 2011 found that both state and federal bans on assault weapons resulted in decreased rates of mass shooting fatalities. The federal ban also indicated a decrease in rates of mass shooting injuries.

A 2019 study examined mass shootings from 1981 through 2017 and analyzed the risk of fatalities in those incidents. The study found that during the 10-year period the federal ban was in effect, mass shooting fatalities were 70 percent less likely to occur than either before or after the ban.

Research from Stanford University reviewed U.S. mass shootings over a 35-year period. The analysis found that the decade during which the federal assault weapons ban was in effect was linked to a 25 percent decrease in mass shootings and a 40 percent decrease in mass shooting deaths. Additionally, the research found that in the decade after the ban expired, mass shooting deaths increased by 347 percent.*

The ban on high-capacity magazines within the federal assault weapons ban also had an impact:

A Washington Post investigation of the impact of the federal ban in Virginia found that during the years it was in effect, there was a noted decline in the number of guns equipped with high-capacity magazines recovered from crime scenes; the rate reached a low of 10 percent in 2004. After the ban expired, this rate increased, reaching 20 percent in 2010.

A 2019 study analyzing mass shootings that were committed between 1990 and 2017 found that 77 percent of mass shootings perpetrated with a high-capacity magazine occurred in states that did not have state-level bans on these specific ammunition-feeding devices.*

What happened when the federal ban expired?

Following the expiration of the ban in 2004, assault weapons and high-capacity magazines once again became legal to manufacture and purchase, and the gun industry responded with renewed fervor, flooding the civilian consumer market with these guns. Since the expiration of the federal ban, assault weapons and high-capacity magazines have been used to perpetrate some of the deadliest public mass shootings in modern U.S. history:

On August 3, 2019, in El Paso, Texas, 46 people were shot, 22 fatally.

On February 14, 2018, in Parkland, Florida, 34 people were shot, 17 fatally.

On November 5, 2017, in Sutherland Springs, Texas, 46 people were shot, 26 fatally.

On October 1, 2017, in Las Vegas, 480 people were shot, 58 fatally.

On June 12, 2016, in Orlando, Florida, 102 people were shot, 49 fatally.

On December 14, 2012, in Newtown, Connecticut, 28 people were shot, 26 fatally.

On July 20, 2012, in Aurora, Colorado, 70 people were shot, 12 fatally.

Not only do these highly dangerous firearms and accessories continue to be used in horrific mass-casualty shootings, they are increasingly being used in cities that experience high rates of gun violence. A 2017 study found that guns equipped with high-capacity magazines made up between 22 percent and 36 percent of crime guns in the United States. A 2010 report from the Police Executive Research Forum noted that more than one-third of U.S. police agencies reported increased use of assault weapons following the expiration of the federal ban. In 2018, Baltimore Interim Police Commissioner Gary Tuggle stated that one-third of guns recovered in criminal investigations were equipped with high-capacity magazines. The Baltimore Police Department recovered 890 firearms with high-capacity magazines from January 1, 2017, through April 29, 2018.

The ban’s expiration has also been linked to changes in international firearms trafficking. Assault weapons and high-capacity magazines are desirable weapons for organized crime and cartels in Mexico. A 2013 study found that following the expiration of the ban, Mexican municipalities bordering Texas, Arizona, and New Mexico reported increased levels of gun homicides. Municipalities near California did not see similar increases, likely due in part to the state-level ban on assault weapons.

* Update, November 5, 2019: This fact sheet has been updated to reflect research published in fall 2019 on the efficacy of the federal assault weapons ban and of state-level bans of high-capacity magazines in the United States.

Endnotes