He was a platoon guide in an assault on a camouflaged entrenchment defended by machineguns, rifles, and mortars. When his men were pinned down by 2 enemy machineguns, he voluntarily advanced under heavy fire to within 20 yards of 1 of the guns and attacked it with a hand grenade. The enemy, however, threw the grenade back at him before it could explode. Arming a second grenade, he held it for several seconds of the safe period and then hurled it into the enemy position, where it exploded instantaneously, destroying the gun and crew. He then moved toward the remaining gun, throwing grenades into enemy foxholes as he advanced. Inspired by his actions, 1 squad of his platoon joined him. After he had armed another grenade and was preparing to throw it into the second machinegun position, 6 enemy soldiers rushed at him. Knowing he could not dispose of the armed grenade without injuring his comrades, because of the intermingling in close combat of the men of his platoon and the enemy in the melee which ensued, he deliberately covered the grenade with his body and was severely wounded as it exploded. By his heroic actions, S/Sgt. Cooley not only silenced a machinegun and so inspired his fellow soldiers that they pressed the attack and destroyed the remaining enemy emplacements, but also, in complete disregard of his own safety, accepted certain injury and possible loss of life to avoid wounding his comrades.