Gardai have already responded to one serious incident involving the realistic Beretta 92-style guns.
Senior gardai believe the mob has been producing pipe bombs for dissident Republicans and organised criminal gangs.
Sources say that the firearm has been designed to look like a version of a Beretta 92 – one of gangland's most lethal handguns.
In a serious incident just this weekend, Garda reinforcements had to be called in after a major public disorder incident involving the gang in Darndale.
The gang, made up of Traveller criminals and based in Coolock, is now a major target for gardai and rival criminals, and some of its leaders have been warned recently that their lives are under treat.
Last month, gardai carried out searches at properties linked to the mob as part of an investigation into dissident Republican activity in Dublin.
They arrested a 28-year-old man who was released without charge. A file has been sent to the DPP.
The Herald has learnt that this man has survived a number of attempts on his life, including an incident where he was shot at in September.
Among the Traveller criminals who have forged links with the Continuity IRA and Real IRA are three men who were arrested by officers from the Special Detective Unit in July over a botched extortion racket.
Ten people were arrested in the operation in Balbriggan in north Co Dublin after the gang first targeted the wrong house.
The group then arrived at the home of a man they had selected as a potential victim.
Wearing balaclavas and scarves over their faces, three or four of the group entered the house while the rest remained outside.
They told their target that he would be shot if he did not meet their demand for a five-figure cash sum. He was then shown a picture of a Republican funeral as a warning.
The Herald has previously revealed that the Real IRA had issued death threats against the Traveller mob for ‘trading' under the IRA name.
A reliable source explained: “The Travellers have been using the IRA name for extortion, intimidation and swindling money – they have been targeting people in their own community.
“They are involved in a number of localised Traveller feuds and claim that they have the backing of the IRA.”
The Traveller criminals are strongly connected to a jailed senior dissident who received a severe beating from other dissidents last summer in Portlaoise Prison.
Sources say that they are responsible for shooting other Travellers in May and burning out their caravans.