Actually, the term "assault weapon" is made up. It is a derivative of the real phrase "assault rifle" which is a selective fire (can switch between automatic and semi-automatic) rifle or carbine firing ammunition with muzzle energies intermediate between those typical of pistol and high-powered rifle ammunition. If you look at the above pictures again, only one of the above is an assault rifle, and that is "B", a M-16. Both the AR-15 (A) and the SIG 556 (C) are semi-automatic only. But the gun grabbers want to ban them because they are evil looking black rifles.
Since there is a very specific definition of an assault rifle, the gun control crowd needed something that sounded similar and scary so that they could apply that label to this scary looking class of firearms. So, they made up "assault weapon". Sounds close enough.
That's right, they made up a type of weapon because the existing name covered guns that were fully-automatic and thus already illegal.
The truth is that most of the firearms they designate as assault weapons are less powerful than many hunting rifles. They can't be fired any more quickly than other guns semi-automatic firearms that happen to be a different color or configuration and don't look as evil. But this isn't about reality, it is about disarmament. If they can play on the public's fears and get them to turn on a group of guns for no reason other than looks, that is one step closer to getting rid of guns altogether. As was pointed out by Kurt Hofmann, the St. Louis Gun Rights Examiner yesterday, an assault weapons ban depends on those lies in order to succeed.
That's the core of it. They are using lies and fear to disarm you.
And where are all those "evil guns" that are destroying Mexico coming from?
And once again they lie. Mentioning machine-guns, grenades and rocket launchers, things that are already illegal in the US and not sold to civilians as reasons to ban other weapons.
The enhanced weaponry represents a wide sampling from the international arms bazaar, with grenades and launchers produced by U.S., South Korean, Israeli, Spanish or former Soviet bloc manufacturers. Many had been sold legally to governments, including Mexico’s, and then were diverted onto the black market. Some may be sold directly to the traffickers by corrupt elements of national armies, authorities and experts say.
And note that threats of mass amounts of drugs and people and even guns flowing over the border are not used to build a fence or try to secure the border. Instead they're being used as an excuse to take away your rights.