In 1994, President Bill Clinton signed an assault-weapons ban, which banned the AR-15 and other similar semiautomatic rifles.
After its ban, mass shootings were down in the decade that followed, in comparison to the decade before (1984-94) and the one after (2004-14)
Once the assault-weapons ban expired 10 years later in 2004, gun manufacturers quickly began production and sales rose.
AR-15-style semiautomatic weapons are civilian versions of military weapons that gun control advocates say aren't very different.
The AR-15, like its military version, is designed to kill people quickly and in large numbers, hence the term assault-style rifle.
The gun industry, gun owners and their supporters say AR-15s are used for hunting, target practice and shooting competitions.
The AR-15 was called "America's Rifle" in a January 2016
The earliest known United States shooting to happen on school property was the Pontiac's Rebellion school massacre on July 26, 1764, where four Lenape American Indian entered the schoolhouse near present-day Greencastle, Pennsylvania, shot and killed schoolmaster Enoch Brown, and killed nine or ten children (reports vary). Only two children survived
There are very seldom reports of mass or multiple school shootings during the first three decades of the 20th Century, with the three most violent attacks on schools involving either arson or explosions.
The early 1980s saw only a few multi-victim school shootings this changes in the 1990
1992-1993 (44 Homicides and 55 Deaths resulting from school shootings in the U.S.)
1993-1994 (42 Homicides and 51 Deaths resulting from school shootings in the U.S.)
1994-1995 (17 Homicides and 20 Deaths resulting from school shootings in the U.S.)
1995-1996 (29 Homicides and 35 Deaths resulting from school shootings in the U.S.)
1996-1997 (23 Homicides and 25 Deaths resulting from school shootings in the U.S.)
1997-1998 (35 Homicides and 40 Deaths resulting from school shootings in the U.S.)
1998-1999 (25 Homicides from school shootings in the U.S.)
1999-2000 (25 Homicides from school shootings in the U.S.)
And then continues into 2000
2000-2001 (19 Deaths resulting from school shootings in the U.S.)
2001-2002 (4 Deaths resulting from school shootings in the U.S.)
2002-2003 (14 Deaths resulting from school shootings in the U.S.)
2003-2004 (29 Deaths resulting from school shootings in the U.S.)
2004-2005 (20 Deaths resulting from school shootings in the U.S.)
2005-2006 (5 Deaths resulting from school shootings in the U.S.)
2006-2007 (38 Deaths resulting from school shootings in the U.S.)
2007-2008 (3 Deaths resulting from school shootings in the U.S.)
2008-2009 (10 Deaths resulting from school shootings in the U.S.)
2009-2010 (5 Deaths resulting from school shootings in the U.S.)