With 255 kills, he's deadliest Seal sniper in US history LONDON: With 255 kills, 160 of them officially confirmed by the Pentagon, Chris Kyle, the retired navy Seal sniper, is the deadliest marksman in US military history. Kyle hesitated the first time he killed a person at long range with a rifle. It was a woman who was about to attack a group of US marines with a hand grenade. The US navy Seal was overlooking an Iraqi town from a shabby building as US forces were still invading the country. The marines didn't see the woman coming. "Take a shot," Kyle's chief told him. Kyle stammered , "But.. " "Shoot!" the chief told him again, the Daily Mail reported. Kyle finally pulled the trigger. But after four deployments to Iraq, he learned to stop hesitating and shoot straight. The report said that during the Second Battle of Fallujah alone, when US Marines fought running battles in streets with several thousand insurgents, he killed 40 people. His feat blows away the previous American record of 109, set by army staff Sgt Adelbert F Waldron during the Vietnam war. Carlos Hathcock, the famed marine sniper who was the subject of the book 'One Shot, One Kill' , killed 93 people as long-range sniper in Vietnam. However, Kyle is still far from being the deadliest marksman in the world. That distinction goes to Simo Hayha, a Finnish soldier who killed 542 Soviet soldiers during World War II. For Kyle's deadly track record as a marksman during his deployment to Ramadi , the insurgents named him 'Al-Shaitan Ramad' - the Devil of Rahmadi - and put a $20,000 bounty on his head.