In March 2013 , the Colorado legislature passed a set of gun control laws , prompted by the movie theater shooting in Aurora , Colorado in July 2012 , as well as the Sandy Hook Elementary School shooting in December 2012 . The laws , which became effective July 1 , limited ammunition magazines to 15 rounds , required universal background checks on all gun purchases , and required gun buyers , rather than sellers , to pay the $ 10 fee for a background check
Sandy Hook Elementary School shooting
Sandy Hook Elementary School shooting
John Morse (American politician)