Despite what the above photo may imply, I'm actually referring to the dog. They've both at various times been characterized as nothing more than killing machines that no clear thinking American would ever want in their home, but just as pit bulls are really just good boys and girls, the AR-15 is ... just another gun. Sure, it looks scarier than most, and it's definitely the weapon of choice if you're looking to kill from a long distance but also on kind of a budget, but beyond that it isn't any more or less dangerous than most other guns.
Contrary to popular belief, it's not an assault rifle. People who use that term are thinking of automatic weapons like the M16. Those guns include a selector switch with an "automatic" setting. When that's engaged, the gun will continuously fire for as long as you hold down the trigger, just like in motherfucking Rambo.
"It's called First Blood, asshole!"
The AR-15 doesn't have this option. You have to pull the trigger each time you fire. It's a semi-automatic weapon, just like countless handguns.
So why is it the preferred weapon of most mass murderers? It's not. Yes, it was used in the mass shootings in San Bernardino and Newtown, but reports that an AR-15 was used in the Orlando shootings turned out to be incorrect. The weapon used in that crime was a Sig Sauer MCX, which kind of looks like an AR-15 but uses a firing system that makes it more comparable to the much deadlier AK-47.
Mother Jones magazine has been tracking mass shootings in the United States since the assault weapons ban was lifted here in 2004. Since that time, they've documented 46 mass shootings, and only 14 involved an AR-15. The deadliest mass shooting in this country prior to Orlando was the 2007 massacre at Virginia Tech, which was pulled off using two handguns. Mass shooters use the guns they have available. Outlawing the AR-15 alone won't impact that in the least.
Sure, you can buy extended clips for the AR-15 that allow you to fire more times before reloading, and savvy murderers can modify it to operate like an automatic weapon, but you can also do all of those things with a handgun, as demonstrated at the 0:34 mark of this mildly terrifying video.
Or in this handy GIF!