The Orlando nightclub shooting that took place Sunday reignited the debate over gun control, and central to that debate has been the AR-15 semi-automatic rifle. Initial reports that shooter Omar Mateen used this gun were incorrect—officials determined on Monday that the gun used in Orlando was actually a Sig Sauer MCXThe Washington Post reported. But the AR-15 was nevertheless used in the Newtown, Aurora, and San Bernardino shootings and is the most popular rifle in the country, according to >PBS.

In response to initial reports about the Orlando shooting, Philadelphia Inquirer reporter Helen Ubiñasbought an AR-15 in a matter of seven minutes to show how easy it was to obtain, and a video showing how easy it is to conceal the weapon went viral.

The rifle's creator, Eugene Stoner, died in 1997, but his family recently spoke to NBC about his intentions when he designed it. According to several of his living children and grandchildren, he created the rifle for use in warfare, not for civilians. "After many conversations with him, we feel his intent was that he designed it as a military rifle," they said anonymously. He was an "avid sportsman, hunter and skeet shooter," but he never used that gun for those purposes, and in fact, he didn't even own one. Before his death, the gun was primarily used by the Army.

But now, the National Rifle Association touts the AR-15's potential uses for civilians. "It is customizable, adaptable, reliable and accurate [and] can be used in sport shooting, hunting and self-defense situations. Civilians can also modify and personalize their AR-15 from carbine-length, stocks, optics, barrels, etc.," reads a blog post on the organization's website, which also claims AR stands for "America’s Rifle," not "assault rifle." AR15.COM, an online community for AR-15 enthusiasts, has over 500,000 members.

"What has happened, good or bad, since his patents have expired is a result of our free market system," Stoner's family told NBC. "Currently, a more interesting question is 'Who now is benefiting from the manufacturing and sales of AR-15s, and for what uses?'"

The National Rifle Association and AR15.COM did not immediately return Complex's request for comment.