AN Army search was under way last night after a soldier lost his gun â an SA80 assault rifle. The Sergeant Major had been using the weapon, which fires 700 rounds a minute, during an exercise in the Brecon Beacons. Military chiefs suspended the exercise and ordered all 900 troops to search for the 5.56mm automatic rifle which was loaded with 20 rounds of blanks. But despite a 12-hour hillside hunt the rifle has still not been found. The missing gun belonged to an Artificer Sergeant Major in charge of a 90-strong group of Royal Electrical and Mechanical Engineers. They were taking part in an exercise with the 14th Signals Regiment based at Sennybridge, Powys, mid-Wales. An insider said: âThe ASM handed the rifle to one of his juniors at a temporary command post while he went off to do some admin. âWhen he got back the command post had moved and he couldnât find his weapon.â The Special Investigation Branch of the Royal Military Police have now been called in. Civilian cops from the surrounding area of Dyfed Powys have also been alerted. A spokeswoman for the Ministry of Defence said: âWe take all losses of weapons very seriously.â How much trouble??