One of the most horrifying aspects of the recent mass shooting in Las Vegas was the sheer number of bullets the perpetrator Stephen Paddock was able to fire. He did so with the aid of “stacks and stacks of magazines” that held as many as 100 rounds each. In this regard, Paddock exemplified a trend in American crime: criminals increasingly seek to carry as many rounds as possible in their weapons.

While the focus since the shooting has been on the bump stocks found affixed to a dozen rifles in Paddock’s hotel room, the devices are almost never reported to be used in crimes. That stands in contrast to high-capacity magazines, which were just as essential to the Las Vegas killing spree.

One new study by researchers at the Center for Evidence-Based Crime Policy at George Mason University and published in the Journal of Urban Health found that high-capacity magazines, or guns capable of using high-capacity magazines, were disproportionately recovered in connection with violent crimes in three cities where data was available:

  • Baltimore: From 2012 to 2014, 16.5 percent of all the guns recovered by police had high-capacity magazines, but for weapons used in violent crime, 21.5 percent had the larger magazines.
  • Hartford: 22.2 percent of all guns recovered by police in 2011 and 2012 were capable of using high-capacity magazines, but with those linked to violent crime, the rate rose to 30 percent.
  • Minneapolis: 25.1 percent of the overall illegal gun haul from 2012 to 2014 could have used a magazine that held more than 10 rounds, but when it came to those used in shootings, the number jumped to 46.3 percent.

The larger magazines and the weapons capable of using them were especially common in murder cases. The study’s authors estimated about 40 percent of weapons used in homicides in any city, in any year, could be equipped with high-capacity magazines.

The study also found that high-capacity magazines and the guns that can accommodate them have become more common. That law prohibited the manufacture and sale of magazines that carried more than 10 rounds. In three cities that provided data for two time periods — Baltimore; Richmond, Virginia; and Minneapolis — police found that the percentage of weapons recovered that were capable of higher magazine capacity increased as more time has elapsed since the 2004 expiration of the federal assault weapons ban.