This is a great article from Survival World and William Kirk's analysis is spot on, especially now knowing from Justice Kavanaugh that they are waiting to pick their case before addressing "assault weapons":
Assault Weapon Bans on Thin Ice After New Supreme Court Ruling - Survival World

In a nutshell, writing the majority (and only) opinion since it was 9-0: 

"On page 13 and into page 14, Justice Kagan refers to AR-15s, AK-47s, and .50 caliber rifles as “widely legal and bought by many ordinary consumers.” She concluded that just because Mexican cartel members prefer these rifles doesn’t make their production or sale unlawful."

This will be powerful and important when a case is finally selected!