An auto-loading firearm that is capable of firing multiple times with a single operation of the trigger.

The term “fully-automatic” is contrasted with “semi-automatic”, which requires the shooter to operate the trigger separately for each shot.

The term “automatic weapon” refers only to fully-automatic firearms and never semi-automatic firearms. It is a mistake to refer to a semi-automatic firearm as an “automatic weapon”.

In the United States, civilian ownership of fully-automatic firearms is restricted under the National Firearms Act of 1934 and the so-called Hughes Amendment of the Firearm Owners Protection Act of 1986. To purchase a fully-automatic firearm, an individual must submit to a lengthy criminal background check, and pay for a $500 tax stamp. Only fully-automatic firearms manufactured before 1986 may be owned by civilians. The limited supply of civilian-legal fully-automatic firearms means that the cost is quite high, starting at several thousand dollars. Thus, civilian ownership of fully-automatic firearms is extremely rare.