More than 400 police officers in London took part in dawn raids as part of an operation against gun crime.
There have been dozens of shootings in Brent this year
Thirteen people were arrested in the operation codenamed Nightlight, which included sharpshooters, dog teams and police in body armour.
The raids in Harlesden, Kilburn, Wembley and Willesden, were the culmination of months of police intelligence work on Jamaican "crews" suspected of links to recent shootings.
Several alleged gang members had already been arrested for murder and weapons offences and police believe they caught several leading Jamaican gang members.
Chief Superintendent Andy Bamber, the Borough Commander of Brent who led the operation, said: "We are committed to tackling gun crime and taking away the power that men of violence have in the community.
"This operation was intelligence-led with information coming from the local community, proving that such information does make a difference in the fight against gun and drug crime."
There have been dozens of shootings in Brent this year with drug gangs competing for control of the lucrative crack cocaine market.