First of all, there is no such thing as the "Assault Weapon Ban of 2013", there is only a draft being considered.
Second, like General Topics, there are few limitations on what any congress critter can submit for a law. Most bill submissions do not even get past committee and mostly serve only a political statements.
Third, this particular bill has been submitted to and reported by committee but there is no expectation that it will pass. Govtrack.us estimates that it has a 19% chance of passing
Fourth, the identical bill in the house has not even been submitted by committee and Govtrack.us estimates a 2% chance of passing.
Perhaps we should wait until at least one version of this bill gets out of committee before getting spun up.