Actual documented prove otherwise. The majority of all killings in the united states, be they mass shootings or otherwise, are committed with handguns, rather than any other type of firearm in existence, simply because they are so much more portable and concealable. It is all about convenience for them, not ballistic superiority.
The AR platform is good from the standpoint a simple switch of the upper will yield you a totally different firearm. A few options for bullet weights renders it useful for hunting but, if you are knee deep in mud and you need a rifle that will always perform with little or no maintenance, give me an AK47 variant. Simple design, caliber big enough to stop larger threats, parts available worldwide, mags are plentiful, and ammo cheap as hell.
