Corporal Nikolas Quintero, a motor vehicle operator, and Lance Cpl Sergio Manzano, a field artillery cannoneer, both with Echo Battery, 2nd Battalion, 10th Marine Regiment, 2nd Marine Division, tighten fuzes onto their artillery rounds before firing the M-777 lightweight 155mm howitzer as part of a Top Gun competition held at Fort Bragg, N.C., May 6, 2014. The competition was part of Rolling Thunder, a biannual field operation in which each battery from 10th Marines comes together to train on their respective weapons systems.