"When you look at what happened in Aurora, a great deal of that damage was from the large magazine on the AR-15. I think we need to have that discussion and say, 'Where is this appropriate?'" Hickenlooper said Wednesday.
After Friday's school shootings, Hickenlooper wrote on Twitter, "We know too well what impact this kind of violence has on a community and our nation."
A visibly emotional President Obama seemed willing to renew debate, calling for "meaningful action" to prevent similar shootings.
Also Friday, Mark Kelly, the astronaut husband of former U.S. Rep. Gabrielle Giffords, who was shot in the head during an attack that killed six people in Tucson, Ariz., last year, said the Connecticut shooting should "sound a call for our leaders to stand up and do what is right."
"This time our response must consist of more than regret, sorrow, and condolence," Kelly said on his Facebook page, calling for "a meaningful discussion about our gun laws and how they can be reformed and better enforced to prevent gun violence and death in America."
Tom Sullivan, whose son Alex also died in the Aurora theater shooting, welcomed the discussion.
"Clips that hold 50 bullets? The only animal you're after with that is man. There is no other reason. That's what that is used for. My question to those people is, 'Why do you need a clip that holds 50 bullets?'" Sullivan said in a phone interview.
But Sullivan said mental health, not gun control, is a more pressing concern.
"We all need someone in our lives to care," Sullivan said. "If we see a friend, a colleague, a co-worker and they're having a hard time, we need to reach out."