The Army has been criticised by a coroner after a soldier shot dead a colleague before killing himself at a party where both drink and guns were easily available. Corporal John Gregory, 30, from Catterick, North Yorkshire, fired an SA80 rifle up to 10 times at Seargeant Robert Busuttil, 30, from Swansea, at a barbeque in Afghanistan. The incident occured while both men were on peacekeeping duties in Kabul last August. Wiltshire coroner David Masters recorded verdicts of unlawful killing on the death of Sergeant Busuttil and suicide on Corporal Gregory. Mr Masters, speaking at Chippenham Magistrates Court, called on the Army to tighten its rules on alcohol and gun security. "It has been said that alcohol and lethal, loaded weapons as a lethal cocktail just do not mix," he said. "This incident may be a one-off but my concern is to prevent it from becoming a two-off, a three-off or more." Corporal John Gregory's widow spoke at the inquest The three-day inquest had heard how the two men had fought at the party, shortly before Corporal Gregory returned with his loaded gun. The court was told Corporal Gregory was two-and-a-half times over the drink drive limit, despite orders rationing beer to just two small cans a day. On Tuesday, his widow Annette blamed his actions on anti-malaria medication, saying the drugs had affected his moods. She denied claims from other soldiers that her husband had been aggressive and could get "punchy" when drunk. Recalling the horrific events of 16 August, Mrs Gregory said: "What happened just wasn't John. He would never do anything so completely rash and irresponsible. "I think the anti-malaria tablets could have been a factor here - there is no other way to explain it." Loaded weapons Referring to the drugs, pharmacologist Colonel Graham Stewart, of the Royal Army Medical Corps, said: "Chloroquine can rarely cause psychotic effects in individuals but this is not fully understood. "I estimate it to be a one in 500,000 chance," he said. "It is much more likely that Corporal Gregory's psychotic episode was the result of the direct ingestion of alcohol." The inquest heard how soldiers in Kabul - and especially the 12 stationed with the bulk fuel installation at Bagram Airport - often flouted the so-called "two can" drinks rule. A weapons expert was critical about unit policies which allowed soldiers to have easy access to their loaded rifles whilst being able to drink. Captain Andrew Riddell, of the Small Arms School Corps, based near Brecon, south Wales, said: "This was a very unusual situation. Mixing alcohol with loaded weapons is a lethal cocktail."