The boy was under arrest yesterday after the late night incident on Sunday.
Gardaí at Henry Street described the incident as “serious” and confirmed the teenager was held under Section 30 of the Offences against the State Act. Gardaí did not divulge the make of the firearm.
It is believed the boy’s father had been injured in an earlier fight which occurred in a Limerick city centre pub at around 11.30pm on Sunday.
The boy’s father, in his 40s, had to be taken to the Mid-Western Regional Hospital where he was treated for injuries said not to be life-threatening.
About a half hour later, the boy – on learning of the incident involving his father – armed himself with a handgun and went to the Rossa Avenue area off Mulgrave Street.
He went to a certain house and confronted a person he met on the street outside the house.
As words were exchanged the boy pulled the gun and the third party dived for cover.
A uniformed Garda patrol, which was in the area at the time, saw the youth run off. After a short pursuit, the gardaí apprehended the youth and found the gun.
However, the incident is not connected to ongoing feuds in the city.
The weapon, it emerged, has been sent to the Garda ballistics section in Dublin for a technical examination.