Gardaí seized a firearm and ammunition in Clondalkin yesterday.
The discovery was made when two men were stopped and searched at St. Marks Drive by gardaí from Ronanstown GardaStation.
The men were arrested and taken to Lucan Garda Station where they are now detained under Section 30, OffencesAgainst the State Act, 1939.
Both men, aged 21 and 33, are from west Dublin.