(CNN) -- In the biggest fight over firearms since December's massacre at a Connecticut elementary school, gun-control advocates are poised to notch a victory in an unlikely place.
Colorado Gov. John Hickenlooper is set to sign measures Wednesday that will require universal background checks for gun sales, restrict the size of ammunition magazines and make buyers pay for their own background checks.
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.
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.
Phillips was en route to Colorado on Tuesday to join Hickenlooper at the signing ceremony and praised the governor's support for the bills.
"We're not going be able to stop 100% of the carnage, but we have to start somewhere," she said.
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.
"We're supposed to be a wildlife state. Now it's not going to be seen as that," DeCarlo said.
Erie-based magazine manufacturer Magpul Industries said the legislation will force it to leave Colorado "almost immediately" and urged voters to take out their anger at the ballot box.
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.
"If the dealers can't make any money at $10, they're not going to do it," Taylor said. Under those circumstances, "How are people going to legally transfer a firearm?"
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."
But firearms supporters are facing "the perfect storm" in Colorado now, he said. Democrats now control the statehouse, and they're being prodded "by powers from Washington" to push for new limits on firearms, he said.
"It's not actually the will of the people," Taylor said. "It's just that they've got control of the House and Senate, and we've got a Democratic governor."
That's partly because Colorado has changed, as Taylor put it, "from the old, rugged West" to a "kind of mini-California" in the last 15 years. Jill Hanauer, the president of the Denver-based political consulting firm Project New America, said Colorado is more urbanized and diverse today than it was a decade and a half ago.
"The demographics are such that you have a young state, a state that has experienced rapid growth," Hanauer said. A growing Latino population, "while they are gun owners, they support gun safety measures," she said.
"The combination of shifting demographics that have taken place in Colorado, the tragedies that we've seen and pragmatic leadership all makes it possible to pass these laws that probably could not have been even considered 10 years ago."
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."
Many other state legislatures are debating gun laws in the wake of the Newtown killings, but not all of them are aimed at restricting guns.
Many of the more than 1,000 bills pending around the country would nullify the effect of any federal ban on firearms, assault weapons and high-capacity ammunition magazines, according to the National Conference of State Legislatures.
And nationwide, a CNN/ORC International poll out Monday suggested that support for major restrictions on guns may be fading three months after the Newtown killings. While a majority of Americans favored major restrictions on guns or an outright ban in the immediate aftermath of that massacre, support for gun control has fallen to 43% since that December tragedy, the poll found.
CNN's Thom Patterson, Carma Hassan, Halimah Abdullah, Holly Yan and Tom Cohen contributed to this report.