By Scott Malone

BRIDGEPORT, Conn. (Reuters) - The maker of the assault rifle used to kill 26 children and educators at a Connecticut school in 2012 argued on Monday that attempts to limit the sale of such weapons to civilians are best left to lawmakers and not families of the victims who sued the company.

A lawyer for Bushmaster Firearms LLC, which manufactures the AR-15 that 20-year-old Adam Lanza used in his attack on Sandy Hook Elementary School in Newtown, told a Connecticut judge the 2005 federal Protection of Lawful Commerce in Arms Act (PLCAA) prohibited the suit.

"It's not the role of this court or perhaps a jury to decide whether civilians as a broad class of people are not appropriate to own these kinds of firearms," James Vogts, an attorney for Bushmaster's parent company, Remington Arms, told a courtroom so packed that more than a dozen spectators were watching the hearing standing in a hallway outside the court.

Judge Barbara Bellis heard arguments eight days after a gunman armed with another model of assault rifle killed 49 people at a gay nightclub in Orlando, Florida.

The judge did not say when she would rule on the gunmaker's request to toss the lawsuit.

The case unfolded on the same day that the U.S. Supreme Court rejected a legal challenge brought by gun rights advocates to laws in New York and Connecticut that ban military-style assault weapons.

The families of nine people who died in the attack sued Bushmaster in 2014 in Connecticut Superior Court in Bridgeport. The lawsuit said the AR-15 should never have been sold to the gunman's mother, Nancy Lanza, because it had no civilian purpose.

"It was Remington's choice to entrust the most notorious American killing machine to the public," said the families' attorney Joshua Koskoff, who denied Vogts' claim that the lawsuit amounted to an attempt to ban assault weapons.

"It's not our job to ban things. That's a legislative decision," Koskoff said. "But just as it's not our job to ban things, it's not the legislature's job to decide when there is a tort claim."

The wholesaler and retailer involved in the sale of the Sandy Hook gun also said the PLCAA protects them from lawsuits having to do with the gun's sale.

Matthew Soto, whose sister Victoria was killed in the Sandy Hook attack, said the Orlando shooting had intensified his desire to fight for accountability by gun makers.

"When I heard the news from Orlando so many emotions went through me, from horror to sadness, grief and disgust," Soto told reporters outside the courthouse. "No other family should have to wait six hours to see if their loved one is alive or dead, but yet so many families have to go through that process in this country because our country cannot come together on the issues of assault rifles."

The U.S. Senate's strongest push in years to tighten gun controls was likely to fall short on Monday. Lawmakers scrambled to forge a compromise that might keep firearms away from people on terrorism watch lists by later this week.

Adam Lanza began his Dec. 14, 2012, attack by shooting his mother dead in their home and ended it by turning his gun on himself as he heard police sirens approach.

(Additional reporting by Mike Wood; Editing by Howard Goller and Diane Craft)