In the hands of mass killers and terrorists, the AR-15 (often, the specific ammo used is not specified) has easily racked up a tragic number of kills.

We sometimes forget that the military need is different than ours where we tend to want instant incapacitation while a wounded enemy soldier often takes three men off line as the wounded soldier must be evacuated.

If warranted, I wouldn't hesitate to use an AR-15 for self defense. I live in the suburbs, not a remote rural area. My AR remains in the safe until there's a total breakdown of law and order and thugs are running wild in the streets. For routine home/self defense, I rely on a .45 ACP an a 9mm.