Mass shooters tend to favor the AR-15

When a gunman attacked a high school in Parkland, Fla., on Wednesday, killing 17 people, the event marked a depressingly familiar milestone.

As of this week, seven of the 10 deadliest mass shootings in modern U.S. history have all happened since 2007. The Parkland massacre is now the eighth-deadliest attack.

The nation’s mass-shooting problem seems to be getting worse. And the latest, most serious shootings all seem to have one new thing in common: the AR-15 semiautomatic assault rifle.

The AR-15 typically has large magazines, shoots rounds at higher velocities than handguns, and leaves more complex wounds.

In each one of the earlier shootings on the 10-deadliest list — including the 2007 attack at Virginia Tech in Blacksburg, Va., that left 32 victims dead — the shooters carried handguns. (The exception is the 1984 massacre at a McDonald’s in San Ysidro, Calif., where the gunman also used a shotgun and an Uzi semiautomatic carbine.)

But in all of the latest incidents — Newtown, Conn., in 2012; San Bernardino in 2015; Orlando, Fla., in 2016; and Las Vegas and Sutherland Springs, Texas, in 2017 — the attackers primarily used AR-15 semiautomatic rifles.

There are a couple reasons AR-15s are associated with deadlier attacks. They shoot high-velocity .223-caliber bullets that often shatter inside victims’ bodies, creating more devastating injuries than those typically left by larger but lower-velocity handgun bullets.

Shooters also commonly use the rifles with 30-round magazines, which allow them to fire more rounds uninterrupted than the smaller magazines commonly used in handguns.

Nikolas Cruz, 19, the suspect in Wednesday’s attack, was armed with at least one AR-15 semiautomatic rifle and “countless magazines,” according to Scott Israel, Broward County sheriff.

Of the 10 deadliest mass shootings, Cruz is the only suspected gunman who escaped, survived and will likely face trial — giving the public a chance to learn why the massacre happened.