Four people, including a 14-year-old girl, accused of firearms offences have been remanded to custody.
The girl is accused of conspiring to supply firearms, including revolvers and a machine pistol, and possessing illegal weapons and ammunition.
A youth of 16 is charged with possessing a revolver, cocaine, cannabis and five CS sprays.
A man of 18 and a woman of 31 also appeared on firearms charges. All are from Colindale in north-west London.
All four appeared at High Barnet magistrate's court on Saturday.
The arrests were made on Thursday in Harrow by the Metropolitan Police as part of Operation Trident, which was set up in 1998 to deal with gun crime affecting London's black community.
Police also recovered other firearms and crack cocaine during the raid.