'Gun free zones' are a result of people trying to do something to help. It's obviously not going to work when surrounding areas are flooded with guns. It'd be like an 'illness free area' in a hospital.
I gave you my opinion on what an assault weapon would be. Some that, relative to other guns, let's you do more damage quickly.
Here is the first definition I found: Although existing state laws use varying definitions for what constitutes an
assault weapon (often determined by the presence of certain features), assault weapons are generally high-powered semiautomatic firearms where each round has up to four times the muzzle velocity of a handgun round.