The four men are believed to be teenagers and all six are being held in stations at Mayorstone, Henry Street, and Roxborough Road, under section 30 of the Offences Against the State Act.
Two loaded handguns and a sawn-off shotgun were also recovered in searches in the Moyross Estate.
The major garda operation took place in Delmege and Pineview Garden, areas which have been the centre of violent attacks over the past three months.
Chief Superintendent Willie Keane, head of the Limerick garda division, said last night’s operation had produced very significant results for the gardaí.
“This is part of the ongoing focus to rid Moyross of criminality,” he said.
Tragic mother Sheila Murray was forced to flee her home in Pineview Gardens early on Sunday morning after bricks were thrown through the front window of her house and smashed through her car.
Ms Murray was last night at the bedside of her two children Millie, six, and Gavin, four, who were badly burned in a fire bomb attack on the family car on September 10.
She has told Limerick City Council that she will not return to Pineview Gardens as she feared for other members of her family.
The city council was yesterday trying to arrange alternative accommodation for her and her children.
A 20-year-old man sustained pellet wounds to the face following a shooting incident in Moyross on Monday night.
It is understood he was standing at the door of a house in Delmege Park talking to another person when a car drove by and a gunman opened fire.
Two shots were fired and the victim received pellet wounds to the face. He was rushed to the Mid-Western Regional Hospital, where his condition was said to be comfortable yesterday.
Gardaí believe the shooting may be feud related.
The victim is not from Limerick and gardaí say he unfortunately had just been in the wrong place at the wrong time.
The incident happened a short distance from where Frankie Ryan was shot dead three weeks ago. He was a known associate of theMcCarthy-Dundon gang.
Gardaí have placed extra uniformed and armedpatrols in the Moyross area. The garda mounted horse and dog units have also been deployed to the huge estate, which has been blitzed with violent incidents over the past four months.