Sometimes crafted out of heavy pieces of metal and fitted with all the features of a real weapon, replica firearms can be nearly identical to the real thing.

The toy guns, which often shoot metal BB’s or Airsoft pellets, look so real that they’ve become a nuisance for Boston cops forced to decide in a split second whether a suspect’s weapon is real, or whether it isn’t.

"Replica guns have become a big issue for us,” Police Commissioner William Evans said in a statement Monday. “We all too often encounter young people who are carrying these fake guns and even though they are fake, the public and police don't know they are.”

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On Monday, Mayor Marty Walsh Monday signed an ordinance banning the use of fake guns in public places. It would allow police to confiscate lifelike firearms, and would allow their owners to pick them back up at a police station, according to a release. Replica-owners under 18 would need a parent’s permission to reclaim theirs, the release said.

The move comes as Boston Police to date have recovered more than 150 fake guns in connection with real crimes, the city said Monday. Police records track dozens of cases of toy weapons alarming neighbors or being used to commit crimes such as holding up convenience stores.

It also follows protests and unrest in Cleveland after police last year shot and killed 12-year-old Tamir Rice, who had been playing in a park with an Airsoft pistol.

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At least one major Massachusetts retailer of Airsoft guns told Metro the new ordinance was a no-brainer.

“This is absolutely the right thing to do,” said Randy Fink, owner of Stronghold Ops, an Airsoft dealer and battle arena in Abington.

Except for a telltale orange tip at the end of the barrel (which, he admits, are not impossible to remove or paint over) the firearms he sells look and feel exactly like the real thing, even to gun-owners. Many come equipped with toy versions of features the pellet-shooting guns don’t need, he said, like bullet shell ejection chambers.

“Every time I put them in a new customer’s hands they say, ‘Wow, this is just as heavy as my real one, or this is exactly like the one I used when I was over in Iraq,’” Fink said. “Every single person says that.”

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The allure, he said, is being able to “role play” with a real gun, minus the firepower – customers include veterans, military hobbyists and even police officers, he said.

It’s also what makes them so dangerous to carry in public. He said he warns customers as soon as they walk out of the store to stash their guns in bags. He also can’t sell replica guns to anyone under 18.

“It’s inherently dangerous to walk around with a toy that looks like a real gun,” Fink said. “It makes sense to me that this should be a law and people should abide by it.”