The outrage at the Rising Sun bar at Greysteel had appalled and disgusted all right-thinking people in the province, Lord Justice Carswell told the men at Belfast Crown Court.
The shooting was one of the most callous and cold-blooded massacres in the catalogue of so many heinous crimes in Ulster, he said.
He told the four men:"On the scale of barbarism which has been perpetrated by cold-hearted practitioners of violence over the last quarter of a century, Greysteel ranks very high."
Survivors of the attack and relatives of the dead looked on as Torrens Knight, 24, Jeffrey Deeney, 23, Stephen Irwin, 24, and Brian McNeill, 26, were jailed for life for their part in the Ulster Freedom Fighters atrocity on 31 October 1993.
The shooting was in revenge for the IRA bombing of a fishmonger's on Shankill Road, Belfast, a week before which left nine Protestants dead.
The UFF burst into the Rising Sun in the village of Greysteel outside Londonderry. Irwin, armed with an AK-47 rifle, was first in. As customers prepared for a Hallowe'en dance, he shouted "Trick or treat" then opened fire on a group of women.
Deeney followed, to give Irwin cover, but his gun jammed after he fired just one shot. Knight, armed with a double-barrelled shotgun, stood guard outside, and McNeill was the getaway driver.
Seven people, including two women, were killed in the bar. Another man died six months later. Eight people were injured.
After the verdict, one of the survivors, Rose Fahy, who lost the use of her left arm after Irwin shot her in the shoulder, said: "I do not feel anything for them, because they felt nothing for us."
The four men pleaded not guilty to all charges when the trial opened on Monday, but changed their pleas on Thursday.Reuse content