When Omar Mateen entered an Orlando, Florida, nightclub on Sunday to carry out the deadliest mass shooting in US history, he wielded a weapon that has been used in massacres from California to Connecticut: a military-inspired semi-automatic rifle.
Though so-called assault rifles account for a small fraction of the United States’ 30,000 annual gun deaths, they have been used in at least 10 mass shootings since 2011, according to a database compiled by Mother Jones magazine.
The AR-15 was developed from the US military’s M-16 rifle, used in the Vietnam War in the 1960s. Unlike the military version, the AR-15 is not fully automatic, meaning users must pull the trigger each time they want to fire a shot. Like the military version, many AR-15s combine light weight with a relatively modest recoil.
An assault rifle is a fully automatic selective-fire rifle that uses an intermediate cartridge and a detachable magazine.
So it’s not an assault weapon then?