Bad speech no matter what the President's intention was... it gives opponents an excellent chance to hang Fast and Furious around his neck. You just juxtapose his "AK47" comment with Fast and Furious and the privilege claim. Another easily preventable political gaffe.
One thing that did occur to me though is the President has the authority to put a real crimp in the AK47 market, at least to the degree that they are imported. All it takes is a decision by the Attorney General that such a firearm has no particular sporting purpose and it no longer reaches the U.S. That also lines up nicely with the other language Spats McGee noted (hunting & shooting; but not self-defense).
This would also be one of the few moves the Obama Administration could make given the current Congressional make-up. The problem from a campaign standpoint is the Brady's can barely fund themselves, so they aren't going to be donating much in the way of cash to his campaign. At best he gives his unhappy base something to chew on; but he will likely stir up his opponents even more with that move.