Colorado governor will sign 3 gun control measures on Wednesday DENVER - Colorado's governor will sign three gun control bills into law on Wednesday, including one banning ammunition magazines with more than 15 rounds in a state that has experienced two of the deadliest mass shootings in U.S. history. The measures that Democratic Governor John Hickenlooper will sign also include a bill requiring universal background checks for gun buyers, and another that requires gun buyers to pay for their own background checks, said the governor's spokesman, Eric Brown. The bills passed both chambers of the Colorado state legislature last week as part of a package of gun control legislation that followed months of heated discussion and pushed Colorado to the forefront of a national gun control debate. State lawmakers have also approved legislation banning online certification for concealed-carry permits. Another measure could bar gun purchases by domestic violence offenders, although Hickenlooper had previously said he was undecided about that measure until he sees the final wording. The passage of those bills comes as the nation reels from several mass shootings last year, including the December massacre of 20 children and six adults at a school in Newtown, Connecticut. That followed a mass shooting in Colorado in July when a gunman opened fire in a crowded premiere of the Batman movie "The Dark Knight Rises" in the Denver suburb of Aurora, killing 12 people and wounding 58 others. Former University of Colorado neuroscience graduate student James Holmes, 25, has been charged with multiple counts of first-degree murder in that case. Colorado was also the site of a 1999 massacre at Columbine High School, where two teenagers shot dead a teacher and 12 other students before committing suicide. Several of the guns used in that attack were bought at gun shows. Following Columbine, the state closed a loophole that allowed firearms purchases at gun shows without a background check. The Colorado legislature's action follows the passage in New York state in January of a sweeping gun-control law that bans assault weapons and magazines that hold more than seven rounds of ammunition, requires gun owners to register most guns with the state and requires universal background checks. President Barack Obama has put forward a number of federal gun-control proposals following the Newtown killings.