There were 1,736 gun crimes in London between April and September
Gun crime in London has risen by 17% over the past year and there was a 20% rise in rapes, police figures revealed.
But the total number of offences fell slightly to their lowest level for a decade, with a fall in murders, youth violence and knife crime.
There were 1,736 gun crimes in London between April and September, Metropolitan Police said - 252 more than in the same period last year.
A police spokesman said the rise was "a matter of great concern".
The overall number of crimes in London fell by 1.2% to 423,458.
Rape has risen by 233 offences to 1,387 and residential burglaries have risen by 9.8% to 29,448.
The Met said it would be "working to improve victim confidence in police" and encourage more reporting of rape offences.
The police spokesman said: "We have improved the way we use intelligence, and the new dedicated command will increase accountability and consistency in the investigation of these crimes."
There was a 4.7% fall in knife crime, 4.5% fewer young people were victims of crime and there were 30 fewer homicides compared to the same period last year.
Deputy Assistant Commissioner Lynne Owens said: "Overall, crime in London continues to fall, which is good news for Londoners.
"Reductions in knife crime, youth violence and homicide in particular represent continuing success in these areas on top of significant reductions last year."
She added: "However, we are not complacent. There are areas that remain a challenge, and we continue to tackle those challenges head on."