Six U.S. representatives representing Maryland, including Maryland Democratic Reps. Anthony Brown and Jamie Raskin, are helping cosponsor a bill outlawing attachments to semiautomatic rifles that allow them to fire faster.

The Maryland lawmakers were among 168 Democrats to cosponsor the Automatic Gun Fire Prevention Act, introduced by Reps. David Cicilline (D-R.I.) and Dina Titus (D-Nev.), on Oct. 4. If passed, the act would outlaw the "bump fire stock" device, which can enable semiautomatic weapons to fire 400 to 800 rounds per minute, according to a news release.

The guns found in Las Vegas shooter Stephen Paddock's hotel had been modified with bump stocks, CNN reported. Earlier this month, Paddock opened fire at the Route 91 Harvest music festival in Las Vegas from the 32nd floor of the Mandalay Bay hotel, killing at least 59 and injuring hundreds more in the deadliest mass shooting in modern U.S. history.

Bump stocks were developed in 2010, said University of Maryland criminology and criminal justice professor Laura Dugan, adding that they can help those with arthritis fire a gun more effectively.

"Evidently … if you have arthritis and you pull a trigger, it hurts to have to do that repeatedly," she said. "Given that, that was the pitch for this particular device."

Rep. Carlos Curbelo (R-Fla.) introduced bipartisan legislation in the House on Tuesday to ban bump stocks. And Dugan said Republicans could be facing pressure from their constituencies on gun control after any mass shooting, such as the one in Sandy Hook in December 2012​, which resulted in the death of 26 people, including 20 children.

"If somebody can essentially convert a semiautomatic weapon by buying one of these and utilizing it and cause the kind of mayhem and mass casualties that we saw in Las Vegas, that's something of obvious concern that we ought to explore," Sen. ​John Cornyn (R-Texas) told reporters on Oct. 4.

"The shooting in Sandy Hook was with semiautomatic pistols, so [Republicans] don't want to give those up," Dugan said. "But because of the way he modified his weapon, they're able to identify something that … can be banned, so therefore they can appease the angry constituents while still allowing the majority of their constituencies who want gun freedoms to be appeased."

Semiautomatic weapons load cartridges automatically into the chamber, but the user has to continue to pull the trigger. But bump stocks allow the user to keep the trigger pulled and the weapon discharges automatically, allowing a semiautomatic firearm to fire automatically.

Aside from a bump stock, Dugan said she wasn't aware of any other ways to modify a semiautomatic weapon.

"What happened in Las Vegas, I think, brought to people's attention an issue that many of us just didn't know existed," Brown said. "While we all know, and we all understand, and most everybody accepts that automatic weapons are prohibited … the bump stock basically converts a semiautomatic into an automatic, and yet wasn't prohibited."

Brown said this would be a common-sense regulation, like the rule in this state requiring licensed arms dealers to do background checks on anyone purchasing a firearm.

Raskin also supports universal background checks on gun purchases, as well as a ban on the sale of high-capacity magazines and military-style assault weapons, similar to state legislation passed in 2013.

"Congress must get serious about comprehensive legislative action for effective policy change," Raskin wrote in an email. "We must work overtime and across the aisle to pass common-sense legislation to lower our obscene rates of gun violence. Our levels of gun violence make us an absolute outlier in the civilized world. Now is the time to act."

​While Dugan said she thinks the bill would help, it could take some time if bump stocks appear on the black market.​

"So do I think [the bill] will help? Yeah, but I think it will take a while," Dugan said. "This particular type of mass shooting is pretty rare, [with a] long-range automatic weapon, but the problem is that now that somebody's done it, copycats could step up and do it."

CORRECTION: Due to an editing error, a previous version of the headline stated the device lawmakers want to ban would quicken machine gun fire. The device would quicken semiautomatic fire. The headline has been updated.