"Today is the day; now is the time," Dave Hoover, uncle of victim A.J. Boik, said during a press conference at the Capitol on Friday.
Gun control is expected to be one of the most heated topics at the state legislature in the coming months.
"Call you congressman, call your senator [and] don't think it won't affect you. I wish I wasn't standing here," Hoover said.
Democrats have signaled they may sponsor legislation to ban assault weapons and restrict access to firearms to people with mental illness. Gov. John Hickenlooper has said the time is right for lawmakers to discuss gun control.
"It's harder for me to adopt a pet than to buy a gun," Hoover said. "If we do nothing from this day forward, we're all complicit in what happens beyond this day."
Twelve people were killed in the July theater shooting and more than 58 others were wounded. The survivors and relatives of the victims spoke on the day the nation held a moment of silence to mark one week since the Connecticut school shooting.
On, Friday, the National Rifle Association broke its silence on the shooting rampage at the elementary school that left 26 children and staff dead.
"The only thing that stops a bad guy with a gun is a good guy with a gun," the group's top lobbyist, Wayne LaPierre, said at a Washington news conference.
LaPierre said "the next Adam Lanza," the man responsible for last week's mayhem, is planning an attack on another school.
"How many more copycats are waiting in the wings for their moment of fame from a national media machine that rewards them with wall-to-wall attention and a sense of identity that they crave, while provoking others to try to make their mark," LaPierre said. "A dozen more killers, a hundred more? How can we possibly even guess how many, given our nation's refusal to create an active national database of the mentally ill?"
He blamed video games, movies and music videos for exposing children to a violent culture day in and day out.
"In a race to the bottom, many conglomerates compete with one another to shock, violate and offend every standard of civilized society, by bringing an even more toxic mix of reckless behavior and criminal cruelty right into our homes," LaPierre said.
(KUSA-TV © 2012 Multimedia Holdings Corporation with The Associated Press)