Interesting that he chose to use the AK47 as an example; when that was not the rifle used in the Aurora shooting. I wonder why they decided to choose the AK47 to pick on? Apparently the Administration is sensitive enough on that issue that it didn't want to risk touching on the American weapon actually used.
Though from a practical perspective, banning the one weapon that was used last and malfunctioned causing the gunman to abandon his plans doesn't strike me as a real efficient way to mitigate spree murders even if you could show that a ban might be effective.
Of course, the opposition isn't interested in mitigating murders or crime. They are interested in banning guns. I think they are just starting to realize that saying so openly was what got them in trouble in the first place and now they are trying to play the "O I believe in the Second Amendment, but who needs one of those" game to start the ball rolling again. The key is to get them to say what is on their mind - most of them will eventually blurt out "We should ban them all!" if you get them talking long enough.