FORT A.P. HILL, Va. -- U.S. Marine helicopters and U.S. Air Force A-10 Thunderbolts will conduct day and night live-fire training here on May 8, 9, 12 and 13. The A-10 Thunderbolts will fire 30 millimeter cannons and drop 25-pound practice bombs. The Marine helicopters will fire machine guns and aerial rockets. All live firing is expected to end by 9:30 p.m. each day.