A majority of firearm related homicides in the United States involve the use of handguns . According to a 2013 analysis by Mayors Against Illegal Guns 14 out of 93 mass shootings involved high-capacity magazines or assault weapons . Nevertheless , AR-15 style rifles have played a prominent role in many high-profile mass shootings in the United States and have come to be widely characterized as the weapon of choice for perpetrators of these crimes . AR-15s or similar rifles were the primary weapons used in around half of the 10 deadliest mass shootings in modern American history , including the 2012 Sandy Hook Elementary School shooting , the 2015 San Bernardino attack , the 2017 Las Vegas shooting , the 2017 Sutherland Springs church shooting , and the 2018 Stoneman Douglas High School shooting . Gun expert Dean Hazen and mass murder researcher Dr. Pete Blair think that mass shooters ' gun choices have less to do with the AR-15 's specific characteristics but rather with familiarity and a copycat effect
Sandy Hook Elementary School shooting
Sandy Hook Elementary School shooting
AR-15 style rifle