Just recently picked up my latest U.S. military assault rifle. It has a bayonet lug so it is an assault rifle.
This new rifle is capable of fast repeating fire. Much faster that the old rifle it replaced. It is quickly loaded by simply dumping a handfull of ammo into its loading port. Its ammo capacity is a full five times what its predecessor had.
The ammo used in this new rifle has almost twice the velocity of the rifle it replaced. Not only that this ammo is the first U.S. military ammo to use a new propellant that can be fired all day without a need to clean the barrel of residue. This propellant also does not give away your position like the previous one did. With this you can remain hidden. Handy for snipers.
While many might say that the founding fathers never foresaw a weapon that could be fired multiple times without giving away the shooters position and try to ban it. After all who needs such a weapon?