Hawaii lawmakers are advancing a bill to explicitly ban “bump stocks” similar to the devices that were used in last year’s massacre of 58 concertgoers in Las Vegas, but that effort is being opposed by dozens of local firearm enthusiasts.

Senate Bill 2046 would prohibit trigger modification devices including bump stocks that function in a way that accelerates the rate of fire of a semi-automatic firearm, and would make possession of those gadgets a felony punishable by up to five years in prison.

Maui Deputy Prosecuting Attorney Richard K. Minatoya said the bill “will prohibit people from circumventing automatic-firearm regulations with devices that may currently be legal.” Examples are the bump stocks used in the Las Vegas shootings, which gave semi-automatic firearms the same effect as an automatic firearm, he said in written testimony.

The bill to ban the devices is backed by the Honolulu Police Department, Hawaii island Mayor Harry Kim, Americans for Democratic Action in Hawaii and a handful of other private individuals and law enforcement officials.

However, more than 100 people and organizations submitted testimony opposing the bill. Most argued that the measure would effectively outlaw legitimate shooting accessories other than bump stocks.

“The broad and overreaching provisions of SB 2046 could criminalize firearm modifications such as competition triggers, muzzle brakes, and ergonomic changes that are commonly done by law abiding gun owners to make their firearms more suitable for self-defense, competition, hunting, or even overcoming disability,” wrote Daniel S. Reid, state liaison for the National Rifle Association of America.

Stephen Paddock used rifles fitted with bump stocks to help him spray gunfire into a crowd of about 22,000 concertgoers last year, killing 58 people and causing wounds or injuries to more than 800 others. Paddock then killed himself in the worst mass shooting in modern U.S. history.

According to national news reports, at least a dozen of the 23 firearms that Paddock stockpiled in a suite he rented at the Mandalay Bay hotel were equipped with the bump stock devices.

A bump stock is essentially a slide mechanism attached to a modified rifle stock that can be swapped with the original stock of a weapon. When the modified rifle is fired, the recoil pushes the front portions of the weapon back and forth along the slide in a way that allows it to simulate automatic firing.

There is some disagreement over whether bump stocks are legal in Hawaii, which has some of the strictest gun control laws in the nation.

Hawaii Rifle Association President Harvey Gerwig said bump stocks are legal here, but former Attorney General Doug Chin opined they already are banned under existing Hawaii law that prohibits modifying firearms to convert them into automatic weapons.

State Sen. Karl Rhoads, who is a lawyer, said it isn’t clear to him that bump stocks are in fact banned here. He introduced SB 2046 to make the ban explicit, and the measure was co-sponsored by several of his colleagues.

Rhoads said he was “a little surprised” at the pushback the bill has received.

“Having said that, I shouldn’t have been surprised because the NRA has been taking an extremely hard line. No matter how common-sensical, they’re just opposed to everything, and I think this is a prime example,” said Rhoads (D, Downtown-Nuuanu-Liliha). “Why in the world would you be opposed to banning bump stocks?”

Gerwig said the problem with the bill is it encompasses any modification of a firearm that might make it shoot faster, such as installing an after-market trigger commonly used by target shooters. “Now all of a sudden you’re a felon with a five-year sentence,” he said.

According to a study led by Dr. Michael Siegel of the Boston University School of Public Health, Hawaii historically has had the lowest rate of gun ownership in the nation.

That study covered close to 30 years, from 1981 to 2010 in all 50 states, and found a “robust correlation” between estimated levels of gun ownership and gun homicides at the state level. Gun ownership in Hawaii averaged 25.8 percent during those years.

The U.S. Centers for Disease Control and Prevention calculated Hawaii’s firearm mortality rate at 4.5 deaths per 100,000 population in 2016, which was lower than all but three other states.

SB 2046 now advances to the Senate Judiciary Committee for further consideration. House Bill 1908, which also seeks to ban bump stocks and similar devices, has been approved in the House Judiciary Committee, and is now positioned to advance to the House Consumer Protection and Commerce Committee.