A few nights ago, talk show host Bill O’Reilly claimed “automatic” weapons were available to the public at gun shows and local gun shops. O’Reilly kept referring to “AK” rifles. O’Reilly was embarrassingly off the mark, but his was a common mistake. An assault rifle is a shoulder fired rifle chambered to a rifle caliber (as opposed to a sub-caliber such as 9mm). The assault rifle is capable of automatic fire: multiple shots with a single pull of the trigger (machine gun style). The AK-47 is such a rifle. Originally the service rifle of the Soviet Union, the AK-47 was supplied to communist-friendly groups and governments all around the world. The Soviets  replaced the AK-47 with a lighter caliber version as the U.S. had replaced the M-14, with the smaller caliber M-16.
A semi-automatic rifle is only capable of firing a single round per every pull of the trigger. Semi-automatic rifles are commonly available through licensed gun dealers throughout the United States. Manufacturers offer semi-automatic rifles that look like the AK-47 and the M-16 but are not assault rifles. The gun control crowd is obsessed with “military style” weapons – that is, long arms that look like assault rifles. The big complaint has been magazine capacity, hence the Assault Weapons Ban. In real life, any number of quality hunting rifles offer greater power, speed, and reach then the military-type rifles, one simply need take a second to pop in another magazine.
Fully automatic weapons and sound suppressed weapons are available in the United States to individuals who request a special transfer tax certificate from the federal government, undergo a background investigation, and agree to submit to inspections by federal agents. My late father went through that process to obtain a sound suppressed .22 rifle to control vermin without disturbing his neighbors.  There are relatively few automatic or sound suppressed weapons in the hands of U.S. citizens.
True automatic weapons are rarely used in crimes and those that are most often enter the U.S illegally . There is no “Assault Rifle” crisis, just ignorance and an unwillingness to deal with crime.