Everytown President John Feinblatt today just admitted that AR-15's (and thus weapons like them) are in common use.
Why is this admission by the president of Mike Bloomberg's gun control group important? Well, the ruling in DC v Heller, a SCOTUS ruling, which states:
The Second Amendment protects an individual right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home.
United States v. Miller, 307 U. S. 174 does not limit the right to keep and bear arms to militia purposes, but rather limits the type of weapon to which the right applies to those used by the militia, i.e., those in common use for lawful purposes. Pp. 47–54.
Case closed, so thanks, Mr. Feinblatt, for saying that AR-15's are not only in common use (severe overwhelming majority which is for lawful purposes), but that they're also one of the top 4 selling types of firearms in the US (and that 1 in 20 Americans had one), thus banning/restricting them different than other common arms is unconstitutional.