Colorado Gov. John Hickenlooper on Wednesday signed three gun-control measures into law, including one that will require universal background checks for gun sales.
The measures also will make buyers pay for their own background checks and limit ammunition magazines to 15 rounds.
The Colorado laws go into effect July 1.
New York passed new gun-control legislation after the December killings at Newtown Elementary School, but it already had some of the stiffest gun laws in the country.
Colorado, where firearms are almost as much a part of the landscape as the Rocky Mountains, is a different case.
It's long been a politically conservative state, voting Democratic just once in the 10 presidential elections that followed Lyndon Johnson's 1964 landslide. But in recent years, its political center of gravity has tilted leftward: It went for Barack Obama in 2008 and 2012, voted to legalize recreational marijuana last year, and state lawmakers this year voted to allow civil unions for same-sex couples.
Then there's also the bloody history of the past decade or so -- the mass shootings at Columbine High School in Littleton and a movie theater in Aurora, both Denver suburbs.
Still, it took the December killings at Newtown "to really wake up America's conscience and realize that there were better solutions," said Sandy Phillips, whose daughter, Jessica Ghawi, died at Aurora.
Gun-rights advocates call the Colorado bills unenforceable, feel-good measures that are likely to backfire.
Nick DeCarlo owns a 2,000-acre bird-hunting preserve in Wiggins, on the prairie northeast of Denver. He says his clients are unhappy with the new legislation, particularly language that limits shotguns to eight rounds.
"They're upset to the point where it's like they feel Colorado is being stereotyped as a gun-control state," DeCarlo said. That's going to keep businesses from moving to the state and hunters from visiting, he said.
Already, he said, out-of-state customers are telling him they've made their last visit.
Richard Taylor, a manager at the Aurora gun store and range Firing Line, said the 15-round restrictions on rifle magazines are "poorly worded" and are likely to affect owners of nearly every magazine. He said sheriffs consider the new legislation unenforceable, and the $10 limit on charging individual buyers for background checks is far below the $50 a store typically charges for handling a transfer.
Phillips said the obstacles are small compared to the potential price.
"Let's say it takes $10 and 10 minutes of your time, and it's going to protect somebody from getting a gun that they shouldn't have," she said. "Ten dollars and 10 minutes is worth the time that it takes to save a life."
Colorado voted to make background checks for gun-show purchases mandatory after Columbine, when investigators learned that the weapons used by the teenage killers were bought by an 18-year-old at a gun show to avoid a background check. The buyer, Robyn Anderson, later told a state House of Representatives committee that the gun purchases had been "too easy."