Mass shootingAR-15: The most popular assault-style rifle in the United States

The gunman who killed dozens of people in Aurora, Sandy Hook, San Bernardino, and, yesterday, Orlando all used an AR-15 rifle.

According to the National Rifle Association (NRA), the gun, which was designed by ArmaLite for the U.S. Army and originally produced by Colt in the 1960s, is the most popular rifle in the United States. It is lightweight, holds high-capacity magazines, and is relatively easy customization.

DW notes that for a decade, the Federal Assault Weapons Ban (AWB) banned the purchase of the AR-15. Congress passed the AWB in the wake of the 1989 death of thirty-four children and a teacher in Stockton, California at the hands of a gunman using an AK-47 semi-automatic rifle. The purpose of the AWB was to prevent would-be mass-shooters from exploiting t the accuracy and speed of guns such as the AR-15 and AK-47 can facilitate.

In 1994 President Bill Clinton signed the AWB into law as part of a larger crime bill. The AWB had a 10-year sunset clause, and in 2004 the U.S. Congress allowed the law to expire without extending it.

A lawyer representing the families of victims who died at Sandy Hook Elementary School in Newtown, Connecticut — and who are now suing the gun’s manufacturers for negligence – said that since retaining its full legal status, the AR-15 has become the “gold standard for the mass murder of innocent civilians.”

Following the Sandy Hook mass shooting, the AR-15 cannot be sold in Connecticut, New York, Maryland, and a few other states.

The NRA has argued that the AR-15 is useful as a hunting rifle, but both advocates of gun safety laws and gun rights agree that hunters regard the AR-15 as unsuitable for pursuing game at a distance.

Omar Mateen, the Orlando terrorist, was investigated by the FBI in 2013 and 2014 for possible ties to terrorism, but the investigation yielded no concrete results and Mateen was not found to constitute “a substantive threat.”

He legally purchased his weapons, at least one of them an AR-15, a few days before the shooting. Even if the FBI had found more substantive evidence about his ties to terrorism, it would not have prevented him from legally purchasing weapons. Individuals with suspected connections to terrorism – but not enough evidence to bring charges against them – may be placed on the No-Fly List and prevented from boarding a plane, but unless charges are brought against them in court, they cannot be prevented from legally buying a weapon.

USA Todayreports that in its 2013 address to U.S. Congress, the National Shooting Sports Foundation estimated that between 5 and 8.2 million assault-style rifles are privately owned by U.S. citizens. Online magazine Slate, in a surveyconducted in 2012, concluded that 3.3 million of those were AR-15.