Gardaí are questioning three men and two women after a sawn-off shotgun, ammunition and cash were recovered after officers stopped a car on the M7 in Co Tipperary.
Gardaí stopped and searched the car near Knockalton yesterday.
All five people - aged between 19 and 22 - were arrested at the scene.
They are being held at Nenagh, Thurles and Templemore Garda Stations.