Like most mass shooters, the Virginia Beach gunman used a handgun. And like a growing number of American gun-buyers, he had a preference for some of the most powerful weapons available on the market.

According to police, the man who killed 12 municipal employees in the Virginia city on May 31 was armed with two handguns equipped with extended magazines and a suppressor. The pistols were chambered in .45 caliber. A gun’s caliber refers to a round’s diameter, and simple physics shows that the amount of energy a bullet carries is determined by its speed and mass. As a result, bullets get more destructive as they increase in size and velocity. That makes a .45 deadlier than a tiny .22 when aimed at the same target.

The .45-caliber semiautomatic handgun has been a mainstay in American gun culture for generations. For most of the 20th century, it was the favored sidearm of the American military. But civilians typically stuck with revolvers and small, cheap semiautomatic handguns like the .22, .25, and .32. Only in the late 1980s and 1990s did production of medium- and high-caliber handguns ranging from the .380 to the .45 outstrip that of revolvers and smaller semiautomatics.

While the gun market as a whole has markedly expanded since 1990 — including the production of traditional revolvers and some lower-caliber semiautomatics — medium- and high-caliber semiautomatics have grown at a faster rate.

A Trace analysis of manufacturing data compiled by the Bureau of Alcohol, Tobacco, Firearms and Explosives shows that production of medium-caliber .380 and 9mm semiautomatic handguns increased nearly five times between 1990 and 2017. Over the same period, production of high-caliber .40-, .45-, and .50-caliber semiautomatic handguns more than tripled (The production of high-caliber revolvers also increased during that time period, though not as much as semiautomatics.) In comparison, the gun industry made just 16 percent more .22 pistols.

Increasingly, high-caliber, semiautomatic handguns are used in crimes. ATF data shows that between 2012 to 2017, law enforcement traces of 9mm weapons increased 98 percent. Traces of .45-caliber weapons increased 40 percent. (The data does not specify the type of gun traced by law enforcement, and some of the weapons could be rifles and revolvers chambered to fire rounds usually associated with semiautomatics.)

High-caliber handguns have been involved in some of the country’s most notorious crimes. The perpetrators of the mass shootings in Charleston, South Carolina, and Thousand Oaks, California, were both armed with .45-caliber handgun. The movie theater shootings in Aurora, Colorado, and Lafayette, Louisiana, both involved .40 handguns.

Research shows that criminals seek out high-caliber weapons. In a 2018 study, Anthony Braga of Northeastern University and David Hureau of the University at Albany interviewed Boston gang members, contacted through an outreach worker. They found that “higher-caliber semiautomatic pistols were most valued on the street,” commanding prices in the illegal market on average $160 higher than medium- or small- caliber handguns, outpacing the differences in listed retail prices between gun models.

“Our interviews suggested that these street users were attracted to many of the same features that interest the typical self-defense-oriented gun buyer — although to an exaggerated degree,” Hureau said in an email. Like most gun buyers, the criminals Hureau and Braga surveyed wanted guns that combine a powerful round with the largest ammunition capacity possible, all in a concealable frame.

As higher-caliber firearms turn up in relatively larger numbers, some researchers argue that this has made for deadlier shootings. In a 2018 paper, Braga and Philip Cook of Duke University examined hundreds of shootings in Boston. In the 367 cases in which police could determine the caliber of weapon involved in a shooting, Braga and Cook found that medium-caliber rounds, like the .380 and 9mm semiautomatic rounds, were more than twice as likely as smaller rounds like the .22 to result in a death. Large calibers like the .40 and .45 were nearly five times more likely than a small round to cause a fatal injury. That’s after the researchers controlled for number of gunshots, location of the wounds, shooting circumstances, and victim characteristics.

Their findings were echoed by the Washington, D.C. Office of the Chief Medical Examiner. A 2018 study found that more criminals are using larger-caliber weapons just as the number of shooting deaths in the District soars, according to The Washington Post, which first reported on the study.