A drug search warrant uncovered a large-calibre revolver at a Noble Park North home.
The Division Response Unit (DRU) executed the warrant about 9.15am on Wednesday 9 November.
Greater Dandenong CIU Senior Constable Riley Wesley said four people were home at the time.
In addition to the revolver, police found a quantity of methylamphetamine or ice, plus other weapons.
They charged a 31-year-old man from Dandenong North with firearm and drug offences.
Detective Senior Sergeant John Bergin established the 20-member DRU at Dandenong police station in late August to tackle drug crime and fugitives across Greater Dandenong, Casey and Cardinia.
