If there really are "over 10 million" "AR-15s and AK-47s" "on the streets", why are they almost never used to commit murder? The gulf between hoplophobes' hysterical rhetoric and what happens in real life is wider than the Grand Canyon.
I doubt the stats are kept, but I wonder whether more murders are committed using .223//5.56 NATO or pistol-fired .22 LR.