Officials have identified the gun used in the Orlando massacre as an AR-15 assault weapon — a civilian version of the military's M16 assault rifle and the same firearm used in numerous mass shootings in America, Slate's Justin Peters reported.

A gunman reportedly used an AR-15 semi-automatic assault weapon to kill 50 people and injure 53 others at a gay nightclub in Orlando, Fla., early Sunday. The attack has prompted renewed calls for a ban on the controversial firearm, which was also used in shootings at a movie theater in Aurora, Colo., and Sandy Hook Elementary School, for example. (A federal ban on the weapons, enacted in 1994, expired in 2004, and repeated efforts to reinstate it have failed.)

"Gun advocates have responded with exasperation, saying that, despite appearances, AR-15-style rifles are no more dangerous than any other gun," Peters wrote. The former president of the NRA, David Keene, defended the gun by arguing that it was legally used for "recreational target shooting, hunting, and home defense."

But Peters questioned that logic. After all, the AR-15 is "not particularly well suited, and definitely not necessary, for either [hunting or home defense]."

Slate reported:

"Bolt-action rifles and shotguns can also be used for hunting and home defense. Unfortunately, those guns aren’t particularly lucrative for gunmakers. The lobby’s fervent defense of military-style semi-automatic weapons like the AR-15 seems motivated primarily by a desire to protect the profits in the rapidly growing 'modern sporting rifle' segment of the industry."

The profitability of "modern sporting rifles" such as the AR-15, compared to "bolt-action hunting rifles," raises an interesting question about the gun industry's opposition to an AR-15 ban. The gun and ammunition industries make more than $13 billion annually in revenue, with a $1.5 billion profit, according to NBC News. And a sizeable portion of that profit comes from sales of AR-15-style assault weapons, Peters wrote.

Smith & Wesson - smith-wesson.com

"In its 2011 annual report, Smith & Wesson Holding Corp. announced that bolt-action hunting rifles accounted for 6.6 percent of its net sales in 2011 (down from 2010 and 2009), while modern sporting rifles (like AR-15-style weapons) accounted for 18.2 percent of its net sales," Slate reported.