A blank-firing pistol of the type normally used at the start of track races is to become illegal in the UK after police revealed that it was commonly becoming the weapon of choice in British gang warfare.

The Olympic .38 BBM, which can be readily converted to fire live ammunition, has been used in burglaries, robberies and three attempted murders. The guns are easily available and cost as little as £35 on the internet, or between £60 and £80 on the high street.

But from 4 June, the guns, which are painted bright orange, will be illegal to own in Britain, the Association of Chief Police Officers (Acpo) announced yesterday. Officers have seized 179 converted Olympics from criminals in the past three years. All but 22 of the converted guns have been recovered in London although there have also been seizures across the country, including Bristol, Manchester and North Yorkshire. It is believed that there are at least 1,300 still in Britain.

In an attempt to make sure that those who have bought the guns for legitimate reasons, such as race starting or dog training, are not unfairly penalised, Acpo has launched an amnesty which will run until 4 June and will allow anyone to take an Olympic BBM to their local police station without fear of prosecution. After this date, anyone caught in possession of one could face a five-year prison sentence.

Assistant Chief Constable Sue Fish, the Acpo spokeswoman on gun crime, said that although there was no known case of an Olympic being used in a murder, they were being taken out of circulation because they were a "significant threat to public safety".

Ms Fish said it was not the intention to criminalise those who had bought the guns legally. She said: "We are acting today to deal with the threat posed by criminal use of this firearm. Our action means that any individual in possession of an unconverted or converted Olympic .38 gun should hand it in now or at their earliest opportunity. This targeted amnesty offers a route to dispose of these firearms without facing prosecution for possession."

David Penn from the British Shooting Sports Council said: "The actions of a criminal minority have undermined the lawful use of this revolver and we appeal to anyone in possession of an Olympic .38 BB to hand it in to their nearest police station."

The guns are made in Italy and 1,500 are believed to have been imported into the UK since 2006. Bruni, the manufacturers, have agreed to stop exporting the gun to Britain and they are being recalled from shops.

Although the guns come brightly coloured, criminals paint them black to look like the real thing. Previously ,the only punishment this could bring was a possible conviction for possession of an imitation firearm. As of 4 June, just owning an Olympic, black or otherwise, will be a criminal offence under Section 5 of the 1968 Firearms Act.

Converted guns are a favourite of criminals due to the difficulties they have in readily obtaining live firearms. The Olympic's popularity in gangland circles is down to the fact that it is cheap and can be converted relatively easily.

Ms Fish said further reclassification of other starter-pistols could not be ruled out at a later date but said the BBM had been singled out because "this one is easy to modify". "It is the only one, to our knowledge, to date that has been used to cause significant harm through its criminal use," she said.

Convertors realised that the barrel can be drilled out, making it capable of firing either short-length 9mm ammunition or the blanks it is designed to fire, which can also be converted to make the round live. The converted guns can then sell for up to £400. But due to the crudeness of the conversions, the guns can be erratic, often exploding in the hand of its user.

In London, 12 incidents have been identified where an Olympic was used, the earliest being in March 2007. In March this year a 17-year-old from Islington was convicted of the attempted murders of Mihrac Degirmenci, 25, and Ahmet Baysal, 28. He used an Olympic to shoot at the pair. He will be sentenced on Friday.

In January 2008, James Jones, 25, was convicted of manufacturing firearms and sentenced to 18 months in prison after police found 60 empty Olympic boxes in his flat in Tottenham, north London.

In August last year, Jodie Cousins, 20, left, was sentenced to two years for possession of an Olympic. The gun was found under floorboards in her bedroom. Her said she had been coerced into hiding the pistol.

In numbers: The .38 Olympic

£35: The cost of an Olympic .38 on the internet

£400: The amount the converted guns can fetch when resold on the streets

1,500: The number of Olympics the police believe have been (legally) imported into the UK since 2006

179: Converted Olympics the police have seized across 13 force areas. All but 22 were in London

1: Crimes in London which have been comitted using Olympics since 2007