OK, boomer. The mysterious booming sound that’s been rocking a New Jersey town is apparently the result of a homemade “hail cannon” designed by a vineyard owner to protect his crop from bad weather, he and police told The Post. Rob Butkowski of Hammonton said he’s been firing off the sonically loud cone-shaped contraption — which blasts shock waves up to the sky — to break up cloud formations and scare away birds that nibble his grapes. “It sounds like a jet going by,” said Butkowski, 34. “It’s like the loudest thing you’ve ever heard just blew through your chest — it’s amazing.” Hammonton Chief of Police Kevin Friel said the cannon is responsible for the mystery boom that has baffled and frustrated nearby residents — many of whom have reported the sound to local cops. But the gadget is likely perfectly legal, Friel said.