Cops executing a search warrant in Brooklyn stumbled upon a large cache of weapons and a stash of heavy drugs, authorities said yesterday.

Police took the door at a house in Bensonhurst on 71st Street near 15th Avenue around 9 a.m. Thursday and conducted a room-to-room search, cops said.

The officers quickly discovered eight weapons, including three semi-automatic handguns, three rifles and two shotguns, along with 600 rounds of ammunition.

They also recovered cocaine, marijuana and prescription pills, cops said.

The homeowner, Michael DePietro, 46, was arrested at the scene on charges of criminal possession of a weapon and possession of a controlled substance.