Cpl. Matthew Wilcox is charged in the 2007 shooting death of Cpl. Kevin Megeney at Kandahar Airfield. (Andrew Vaughan/Canadian Press)

A Canadian soldier accused of killing a comrade in Afghanistan was playing a game of quick draw with his gun at the time of the shooting, a court martial heard Thursday in Nova Scotia.

Cpl. Matthew Wilcox is charged with manslaughter, criminal negligence and negligence of duty in the shooting death of Cpl. Kevin Megeney at Kandahar Airfield on March 6, 2007.

After being shot in the chest, Megeney, 25, died in his tent. Wilcox, 23, was charged last October in what the military had originally deemed a "friendly fire" incident.

In his opening address, the prosecutor, Lt.-Cmdr. Robert Fetterley, said Wilcox was careless with his gun and that the death occurred during a "game" he was playing in the tent that night.

Fetterley said the shooting occurred after Wilcox and members of his platoon finished a 12-hour shift at a guard post. Several witnesses are expected to testify that Wilcox was apologizing to Megeney as he was being carried out of the tent on a stretcher.

"We're going to suggest that amounts to ... admissions that he was the shooter," Fetterley said.

Master Cpl. Kyle Keigan testified that Wilcox told him in November or December 2007 that he was playing a game called quick draw when Megeney was shot. "His weapon went off. He didn't know it was loaded at the time," Keigan said Wilcox told him.

The conversation took place either at the garrison in Sydney or at Wilcox's home after they had consumed three to seven drinks, Keigan said.

Under cross-examination, he admitted to not being able to recall precise details of the circumstances surrounding the conversation, which he revealed to senior officers only a few weeks ago.

No one disputes that what happened was an accident, and that's why Wilcox is not charged with murder, Fetterley said.

He went into great detail about strict rules on the Kandahar base regarding the handling of guns and regarding safety procedures, including that soldiers are not allowed to carry loaded weapons.

Cpl. Kevin Megeney, 25, was fatally shot in his tent in Afghanistan. (DND/Canadian Press)

The prosecutor also outlined the safety features of the Browning 9-mm handgun — the weapon that is alleged to have been used to kill Megeney.

For the shooting to happen in light of all the safety precautions points to criminal negligence rather than just a mistake, Fetterley said.

"Our theory is that the accused failed to download his gun, and then when he pulled it from his holster in the tent, he had to pull the trigger, and as a result of that, his friend and colleague was killed. It's as simple as that."

The trial, which is taking place before military judge Cmdr. Peter Lamont in Sydney, is expected to last several weeks and hear from at least 100 witnesses.

Wilcox, of Glace Bay, N.S., and Megeney, of Stellarton, N.S., were both reservists and members of different battalions of the Nova Scotia Highlanders.

In the past, members of Megeney's family, including his mother, said they were convinced the shooting was an accident and they didn't want Wilcox to be charged.

If convicted of manslaughter, the most serious of the charges against him, Wilcox faces the possibility of life in prison.