Devidas Paliutis, 29 and of no fixed abode, pleaded guilty to the manslaughter of Ukrainian Dymtro Grytsunov at Rooney Park in Kilkeel, Co Down in April 2011.
Dublin's Central Criminal Court heard on Monday that Paliutis fired the gun into a group of men, who he was in a dispute with, fatally injuring 30-year-old Dymtro Grytsunov in the chest.
The accused was originally charged with murder, but last November he pleaded guilty to manslaughter.
He also admitted having a sawn-off shotgun and four shotgun cartridges on the same date.
Lawyers for the state told the court that at the time of the offence Paliutis had been unlawfully at
large from Loughan House - an open prison in Co Cavan in the Republic of Ireland.
He was in custody for a separate assault causing harm and was transferred to Loughan House, but walked out the next day.
Paliutis was also freed in error, across the border, from Maghaberry Prison, Co Antrim where he was being held on other charges in September 2010.
He remained unlawfully at large until he was arrested in connection with the Co Down shooting.