If we're talking about statistics, then it should be reiterated, handguns are used to injure and kill far more often than AR-15's. The idea that the AR-15 is more dangerous and thus should be banned completely ignores the realities of how guns are used. On paper the AR-15 MAY look more dangerous (which I'll argue against in a moment), but in execution (no pun intended), they don't contribute to gun violence and death nearly as much as handguns.
Secondly, while we're talking statistics, the reason that AR-15's may seem like a common gun used for violent gun related incidents - again, that involve a long gun rather than a hand gun, which is the minority - is because they ARE common. They are a very common rifle with parts and ammo widely available. It's a platform that has been popular for decades. Does that make it the most dangerous gun out there? No. Does that make it the best weapon a killer can use? No. It's simply a good gun that is very obtainable and popular.
To suggest banning it because it has been used in some massacres or is used with some frequency over other long rifles (which I'd need to see the data on; I've yet to see any) is like saying we should ban 9mm handgun ammo because it's used in more gun related incidents. Which is to say, it's nonsense. 9mm is the most popular round because it's cheap, there's a lot of it out there, most manufacturers make several 9mm models, etc. Does that mean it's the most dangerous chamber for a gun or even handgun out there? No. Does that mean it's the best weapon a killer can use? No. It's simply a popular round that is very obtainable.
Finally, this argument that AR-15's are more deadly than handguns is absurd. You critics point to magazine capacity (as if you can't get heavily extended mags for handguns), to accuracy and easy target acquisition (which means nothing . . . I challenge you folks saying this to explain yourself. In what way is the AR-15 more accurate or easy to acquire targets with? More accurate and easy to acquire targets with than what exactly? What optics system are you referring to? BUIS, holo, etched glass, etc? What accuracy? Compared to what? Certainly not a dialed in hunting rifle . . .), to . . . I don't know what else.
The problem is, you aren't mentioning a certain factor that makes handguns far more deadly than AR-15's: conceal-ability. Don't act as if this isn't a direct factor in making up a weapon's deadliness. The fact that you can hide a handgun (or 3) and use them at your leisure with the element of surprise is a huge one, and lends a deadly edge to handguns, as the majority of gun violence statistics would indicate.
The fact is, AR-15's aren't boogie-men, they aren't mass murder enablers, they aren't the problem here. Disconnected communities where we are isolated and alienated from each other and our environment are the problem, societies where schizophrenia goes unnoticed and depression and autism are on the rise, societies where we glorify consumption, commodification, and marketing, where we see toxic mimicries of all of the fundamentally important relationships and infrastructures that make up a healthy community, etc. The list goes on and on. Guns may be far more efficient tools at killing people than sticks, rocks, or even knives, but they're hardly to blame. We are killing each other for a different reason, and if we want the mass murders, the serial murders, the rapes, the hate crimes, and the other shit to cease, we've got to look at the fundamental structures of our society. Getting rid of one weapon or another won't change a fucking thing. It's a distraction. It won't slow us down. We'll switch to other guns, and if not guns, then fucking dirty bombs or anthrax in light bulbs, or suicide fucking bombs.