Avast, ye scallywags, lower your sails — and give me your wallet.

Two teenage robbers acted like a pair of Blackbeard wannabes when they used a pirate-style, muzzle-loading pistol to allegedly mug a man outside his Brooklyn home.

The antique firearm allegedly wielded by Ariel Ruiz, 19, and Christopher Rivera, 17, was so old that they weren’t even charged with weapons possession, as the museum piece doesn’t fit into the modern definition of a gun under state law.

“It’s pretty crazy. It was like ‘Pirates of the Caribbean,’ ” said a law-enforcement source.

Another source said: “It was more like pirate movie prop than a stick-up weapon. It didn’t even have any gunpowder.”

The teen’s high-seas-style holdup happened in an appropriate place — Bay Ridge — when they waylaid a 46-year-old man near his home close to the Verrazano-Narrows Bridge on Dec. 4, according to documents obtained Tuesday.

Rivera aimed the old-style, long-barreled, black-powder pistol — which was not loaded — at the unidentified victim while Ruiz demanded “Give me your wallet,” according to a criminal complaint.

Despite their weird weapon, the teens were unable to strike fear into the heart of their victim. According to a criminal complaint, the man refused to give up his wallet and “cursed loudly and made gestures thinking that somebody would call 911.”

The teens then punched him in the face and ran into a nearby Dunkin Donuts to hide. The victim, who told The Post that the weapon looked like a “wooden shotgun,” called cops, who quickly tracked down the bungling buccaneers. In the doughnut shop, Rivera and Ruiz were spotted trying to bury their evidence behind a rack of coffee cups.

“That’s where they observe the apprehended take a long [pistol] off of [Ruiz, who] puts the [pistol] behind the rack of cups, and it fell onto the ground, from where it was recovered,” assistant District Attorney Michael Boykin said at Ruiz’s arraignment in Brooklyn Criminal court on Saturday, where he was held on $10,000 bail.

“That was as well captured on the surveillance video.”

Ruiz defense attorney Lisa Salvatore said her troubled client had an upcoming appointment with a therapist she hoped he would be able to make.

“It’s a little unusual . . . I don’t know if it is an operable [weapon],” Salvatore said at Ruiz’s arraignment of the Dec. 5 robbery.

Both teens are due back in court on Thursday.

Ruiz’s mom, Maria Ruiz, 50, said she didn’t know where her son would have gotten his hands on a weapon, let alone such an arcane one. “No, we are a normal family. We don’t have that here. I don’t know where he got it.”

The teens don’t face walking the plank for their crime — but they do face as much as seven years in prison.

According to state law, a person can only be charged with criminal possession of a weapon for having a muzzle-loading firearm if they are a felon.

-Additional reporting by Matt McNulty, Priscilla DeGregory, and Jennifer Bain