Gary Bligh (34), from Rathvilly Park, Finglas, north Dublin, was sentenced to 47 months behind bars at Sligo Circuit Court last week for his role in the operation.
Gardaí suspect pint-sized mobster John Gilligan organised the weapons to be sent from Spain to Ireland.
Bligh was arrested in Castlerea, Co. Roscommon, on September 30, 2020 after Gardaí received intelligence that firearms were being transported from Dublin to a gang in Roscommon.
They stopped Bligh on the Main Street of the town at 8pm that night and found three fully-loaded 9mm Zoraki semi-automatic handguns.
Gardaí also found a small quantity of heroin in follow-up searches on a property in Roscommon linked to the operation.
Bligh is not considered a major player and said he became involved in the transportation of the weapons due to a drug debt.
Gardaí suspect the weapons were shipped from Spain by Gilligan's mob to a Finglas gang, who recruited Bligh.
At the time, Gilligan was trying to re-establish his criminal network from his base in Alicante.
He was supplying a number of gangs - including associates of the so-called Finglas- based 'Monkey Gang' - with quantities of cannabis herb through the postal system.
He was also supplying Traveller gangs in Dublin, who were in turn supplying Traveller gangs around Ireland - particularly in the Midlands.
As well as cannabis, he was supplying Zimovane sleeping tablets, known as 'zimmos', back to Ireland.
Bligh told Gardaí that he thought he was delivering zimmos from Dublin to Roscommon and didn't realise there were guns in the bag - but Judge Francis Comerford said his explanation was not plausible.
Bligh claimed that he was buying cocaine from a childhood friend in Dublin and owed €400.
He said he came under pressure over the debt and was asked to do a job to receive a small payment.
Bligh said he was given a bag containing heavy objects and asked to transport them from Dublin to Roscommon.
While Bligh claimed he never looked in the bag and believed he was carrying sleeping tablets, Judge Comerford said this was not believable, particularly due to the weight of the weapons.
Judge Comerford said while there was no suggestion Bligh was going to use the weapons himself, he had a high level of culpability and was part of the regime of fear that drug dealers operate.
He also pointed out that his drug debt was relatively small and Bligh was willing to engage in serious activity. He said he knew what he was doing wasn't minor and he was going to benefit from delivering the weapons.
Just three weeks after Bligh's arrest, in October 2020, Gilligan was himself apprehended in Spain on drugs and firearms charges.
Gilligan's son, Darren, and Spanish- based Dublin criminal 'Fat' Tony Armstrong were also arrested by cops investigating the gang.
Spanish cops seized four kilos of cannabis and 15,000 zimmos as part of the operation. They also found a .357 Magnum buried in Gilligan's garden in Torrevieja.
Spanish cops said the gun was the same make and model of weapon used to murder crime journalist Veronica Guerin, who was shot dead in Dublin in June 1996 by Gilligan's gang. But sources later confirmed the gun was not the same weapon used to murder Veronica.
Gilligan, his son Darren and Armstrong are all facing trial in relation to the operation. Gilligan's British girlfriend is also facing prosecution.
Armstrong was previously arrested by Spanish cops investigating the murders of 'Westies' leaders Shane Coates and Stephen Sugg, whose bodies were found buried under concrete in a warehouse rented by Armstrong on the Costa Blanca in 2006. He was later released without charge.
While Armstong has been living in Spain for more than two decades, he previously lived in the same estate as Bligh in Finglas on Dublin's northside. He also has links to criminal figures from Artane and surrounding areas in north Dublin.
He is suspected of being a core part of Gilligan's Spanish operation which he started around 2018.
The operation was relatively small by modern standards and a far cry from the massive drugs operation he ran in the 1990s, but Gardaí believe Gilligan was trying to expand it at the time of his arrest.
His arrest dismantled the operation and Gilligan is due to stand trial this year. While out on bail, he has been spotted partying with Dublin criminals in Spain, including convicted drug dealer Anthony Daly from Beaumont in north Dublin.
Daly was videoed with Gilligan on the 25th anniversary of the murder of Veronica Guerin last year as 'The little General' celebrated while a group with him shouted "he didn't do it".
Gilligan was also spotted that same weekend with an Artane man who fled to Ireland after the murder of Hamid Sanambar, who was shot dead as part of a north Dublin feud in 2019. The Artane man later returned to Ireland and was quizzed over the murder before being released without charge.
As well as supplying mobs in Finglas and Traveller gangs, Gilligan was also suspected of supplying Clondalkin-based associates. Gardaí believe he used the postal service to send firearms before his operation was shut down.
Meanwhile, prosecutors in Spain are seeking a prison sentence of eight years and four months for Gilligan on charges of smuggling cannabis, firearms offences and exporting sleeping tablets.
Bligh, who sources say is not considered a major criminal, has already started his sentence back home in Ireland.
Judge Francis Comerford said Bligh was a father of three who was separated from his wife, with whom he had two children, and in a stable relationship with the mother of his third child.
The court was told he was working as a roofer at the time of the offence and was a regular cocaine user.
The judge said he was taking into account Bligh's guilty plea and how he provided gardai with the PIN to his phone after his arrest. He added that he has made substantial steps towards rehabilitation and no longer uses drugs.
He sentenced him to 65 months in prison but suspended 18 months.
Bligh previously competed as an MMA fighter but hasn't fought since 2014 when he had two successive losses at events in Belfast and Dublin.