Assault weapons are no different from firearms typically used for sporting purposes
Design features make assault weapons more deadly than other firearms
Assault weapons are designed to be more lethal than other firearms. In a 2011 report, the Violence Policy Center detailed a trend in firearm manufacturing of militarizing civilian firearms:
The world's armies developed assault weapons to meet specific combat needs. All assault weapons--military and civilian alike--incorporate specific features that were designed for laying down a high volume of fire over a wide killing zone. This is sometimes known as "hosing down" an area. Civilian assault weapons feature the specific military design features that make spray-firing easy and distinguish assault weapons from traditional sporting firearms.
The most important of these design features are--
High-capacity detachable ammunition magazines that hold as many as 75 rounds of ammunition.
A rear pistol grip (handle), including so-called "thumbhole stocks" and magazines that function like pistol grips.
A forward grip or barrel shroud. Forward grips (located under the barrel or the forward stock) give a shooter greater control over a weapon during firing.