A suspected gun and €2,000 worth of heroin was seized by gardaí on Friday afternoon, following a search operation in Dublin 11.
The drugs and firearm were found shortly before 3pm during a planned search of two residential properties in Finglas, and both will be sent for analysis.
Two men, one in his 30s and the other in his late teens, were arrested and taken to Finglas Garda station as a result of the search.
They were detained under Section 4 of the Criminal Justice Act 1984.
The teenager was charged in connection with the incident and is due to appear before the Criminal Courts of Justice on Saturday morning .
The other man was released without charge, and a file will now be prepared for the Director of Public Prosecutions (DPP).
The search was part of Operation Tara, the national Garda anti-drugs operation.