By David Lewis KOULIKORO, Mali (Reuters) - Under a blazing sun and the critical gaze of British and Irish instructors, a line of 11 Malian soldiers lie prone in the dust firing AK-47 rounds at targets, one-by-one. "One out of 10 - not very good," Captain Ibrahim Soumassa, commander of the Malian unit, tells one of the men. "We're at 25 meters. When we're at 100, it'll be difficult." A European Union training mission faces a considerable challenge as it seeks to succeed where years of U.S. ...