Thanks Koolbak. I've been preaching the contents of that link since a week after Sandy Hook. The important and relevant parts:
What counts as an “assault weapon”? The trouble all starts here. There’s no technical definition of an “assault weapon.” There are fully automatic weapons, which fire continuously when the trigger is held down. Those have been strictly regulated since 1934. Then there are semiautomatic weapons that reload automatically but fire only once each time the trigger is depressed. Semiautomatic pistols and rifles come in all shapes and sizes and are extremely common in the United States.
Congress didn’t want to ban all semiautomatic weapons — that would ban most guns, period. So, in crafting the 1994 ban, lawmakers mainly focused on 18 specific firearms, as well as certain military-type features on guns. Complicated flow charts laid it all out. Certain models of AR-15s and AK-47s were banned. Any semiautomatic rifle with a pistol grip and a bayonet mount was an “assault weapon.” But a semiautomatic rifle with just a pistol grip might be okay. It was complicated. And its complexity made it easy to evade.
A 2004 University of Pennsylvania study commissioned by the National Institute of Justice explained why. For starters, only 18 firearm models were explicitly banned. But it was easy for gun manufacturers to modify weapons slightly so that they didn’t fall under the ban. One example: the Colt AR-15 that James Holmes used to shoot up a movie theater in Aurora, Colo., last summer would have been outlawed. Yet it would have been perfectly legal for Holmes to have purchased a very similar Colt Match Target rifle, which didn’t fall under the ban.
While gun violence did fall in the 1990s, this was likely due to other factors [like abortions being legal...]. Here’s the UPenn study again: “We cannot clearly credit the ban with any of the nation’s recent drop in gun violence. And, indeed, there has been no discernible reduction in the lethality and injuriousness of gun violence.”
One reason is that assault weapons were never a huge factor in gun violence to begin with. They were used in only 2 percent to 8 percent of gun crimes. Large-capacity magazines were more important — used in as many as a quarter of gun crimes. But, again, the 1994 law left more than 24 million magazines untouched, so the impact was blunted.