This is a simple overview of the US laws concerning assault rifles (machine guns) laws. Ownership, manufacturing, and sales of machine guns are also covered. A common misconception is that a machine gun (or assault rifle as the media calls them) is a fully automatic weapon. Machine guns are defined as guns that will fire more than 1 rounds each time the trigger is pulled. This can be as little as 2, 3, or many rounds until the magazine is empty. If your gun shoots 2 rounds each time the trigger is pulled, then according the ATF, you have a machine gun. There are several US laws concerning the possession of machine guns. First, under the GCA (Gun Control Act) US manufactured machine guns manufactured AFTER May 19th, 1986 are NOT permitted for civilian ownership under ANY circumstances. Basically this means if you want a machine gun it will have to be a REGISTERED firearm manufactured BEFORE May 19th, 1986.

Once the GCA amended machine guns, owners were allowed to register them into the National Firearms Act Registry. Upon approval, they were issued tax stamps for each machine gun ensuring they were allowed to continue legal ownership. There are commonly referred to as "pre-ban guns" or "transferable machine guns." If the guns were NOT registered at that time (even if they were manufactured before May 19th, 1986) they are now considered illegal machine guns.

There are what some may consider loopholes to legal machine gun ownership. Class 3/SOT license holders are allowed to purchase and deal in post-ban machine guns. You can read more in the article titled HOWTO: Purchase post sample machine guns.

Civilians may learn more about purchasing and owning a pre-ban machine gun in the article titled Buying a machine gun.