A rifle-wielding man and his pal were busted by three NYPD cops in Brooklyn when the officers smelled marijuana and decided to investigate, police sources said.

The Anti-Crime Unit officers smelled the strong odor of pot smoke in the lobby of a St. Johns Place building in Brownsville on Dec. 10 and searched two men who were nearby, police said Tuesday.

They found a loaded Norinco SKS assault rifle with a 30-round high- capacity magazine, 10 envelopes ​filled with heroin, and some marijuana, cops said.

The men, ages 25 and 36, were charged with weapon and drug possession, according to the sources.

Cops tweeted out the arrest, writing, “Outstanding job by Anti Crime and Intell, netted two arrest and the recovery of this Assault Riffle. #OneLessGun.”