Update:
6.40pm – The man has been released without charge while Gardaí have confirmed that a file on the matter will be sent to the Director of Public Prosecutions.
The firearm was stolen in a burglary in Rathfarnham Co Dublin in 2013 and was located at a house in Corofin, Co. Clare.

Earlier: Gardaí in Co Clare have seized a firearm believed to have been stolen during a burglary in Dublin several years ago.
One man was arrested during the armed operation which took place at a property in North Clare at around 10.00pm last night.
Members of the Garda Armed Support Unit were called in to support local armed detectives and gardaí during the intelligence-led operation. A small amount of ammunition was also seized during the raid.
A Garda spokesman confirmed: “A rifle and small amount of ammunition were seized during the operation. The firearm was stolen during a burglary in Dublin some years ago. One male was arrested and he is being detained at Ennis Garda station under Section 30 of the Offences Against the State Act.”
The rifle will be technically examined as part of the investigation into the original theft and subsequent recovery.