HARTFORD, Conn. — Connecticut lawmakers heard testimony Friday for and against proposals to ban bump stocks and regulate so-called “ghost” guns made from parts ordered online, including from teenagers who feared gun violence.

The legislature’s Judiciary Committee held a public hearing at which dozens of people signed up to speak, while more than 300 submitted written testimony. Gun control advocates supported the proposals, while gun rights supporters opposed them.

Two high school students from Bridgeport testified that their own experiences with gun violence — knowing people killed and getting robbed at gunpoint — have made them scared to go to school and walk down the street. They supported the gun control measures.

The hearing came a day before gun violence protests that are planned worldwide, including in Connecticut, in response to last month’s school massacre in Parkland, Florida.

One bill would ban bump stock devices, which are designed to make semi-automatic rifles mimic fully automatic weapons. Democratic Gov. Dannel P. Malloy proposed the ban in January, in response to the October mass shooting in Las Vegas in which the shooter used bump stocks to kill 58 people and injure hundreds more.

“There simply is no reason for these devices to be in civilian hands,” Marty Isaac, president of the board of Connecticut Against Gun Violence, said in written testimony. “Even President Trump agreed these devices should be banned.”

E. Jonathan Hardy, a member of the Connecticut Citizens Defense League, said the vague wording of the bump stock bill could affect law-abiding gun owners. He said the wording that bans “other means of enhancing the rate of a firearm” could apply if he put an aftermarket trigger on his firearm to enhance accuracy for hunting or competing.

Hardy also said the law would not stop people from buying bump stocks out of state or making them with 3D printers.

The other bill would regulate ghost guns, which can be made from parts bought on the internet and mailed to the buyer’s home. The proposal would require people to obtain serial numbers from the Department of Emergency Services and Public Protection, engrave those numbers on the weapons and register the weapons with the state.