Amid boos and groans, a Colorado Senate committee passed a measure Monday that bans ammunition magazines of more than 15 rounds after hours of testimony from a barrage of experts, law enforcement officials and victims of mass shootings.

House Bill 1224 passed on a 3-2 party line vote out of the Senate Judiciary Committee.

Sen. Mary Hodge, D-Brighton, the bill’s sponsor in the Senate, said several recent shooting sprees — including ones in Aurora and Connecticut — were committed with gun magazines that held more than 15 rounds.

“This bill is an attempt to reduce the slaughter,” Hodge said.

The bill, which also limits shotguns to having eight shells, passed through the House chamber by a 34-31 margin in February.

Those testifying in favor of the bill included Patricia Maisch, a woman who helped disable Jared Loughner, the shooter who killed six and wounded 13 people — among them, U.S. Rep. Gabby Giffords— outside a Tucson grocery story in January 2011. Also testifying in favor was Theresa Hoover, mother of A.J. Boik, a victim in the Aurora theater shooting.

Meanwhile, officials with Magpul, an Erie-based manufacturer of ammunition magazines, reiterated their stance that if this measure passes the company will leave the state.

Founder and CEO Richard Fitzpatrick said that staying in Colorado and selling to individuals outside of the state, but not to local residents, is counter to the company’s values.

“The legislation does nothing to improve public safety,” Fitzpatrick said. ”

Moreover, Fitzpatrick argued that the ability to easily modify ammunition magazines would prohibit the sale of almost all of the devices in the state, as the bill precludes sales of magazines that can be “readily converted” to accept more than 15 rounds.

Fitzpatrick noted that some Magpul magazines have a floor plate that is removable to make room for an additional magazine.

Employees urged the committee to vote, they said, to save their jobs.

Committee Republicans balked at the measure.

“These awful tragedies should be prevented, but there’s a real deep disagreement as to how we get there,” said Sen. Kevin Lundberg, R-Berthoud, who argued that the right of ordinary citizens to defend themselves would be infringed.

Supporters included Jane Dougherty, sister of Mary Sherlock, the Sandy Hook Elementary School psychologist who died in the mass shooting that killed 20 children and six adults.

“Simple arithmetic says a smaller magazine needs to be replaced more often than a larger magazine,” argued Dougherty, who said 11 children managed to escape death at Sandy Hook when the shooter had to change gun magazines.

Once the measure received final passage, some in the crowd, a majority of whom were opponents of the bill, shouted “this is unfair” and “you’re taking my guns.”

One man shouted voters will have a final say in November, suggesting that lawmakers could face repercussions on a future Election Day for support of the measure.