One Vietnam veteran I served with in the Marines was a young private in Vietnam, and one night he was on post at the wire with an older sergeant. All was quiet and the sergeant was dozing. Suddenly a screaming VC guerrilla ran through the wire spraying automatic fire. The private shot him numerous times but it didn't seem to slow the attacker down. This was during the Tet (a Vietnamese holiday time, the lunar new year) and the VC was drugged high as a kite and on a suicide mission with tourniquets tied on all his limbs to prevent bleeding out.
Anyway, the scared private turned to the sergeant and said, "He's still coming at us!" The sergeant calmly took aim with his M-203 (an M-16 with attached grenade launcher) and hit the attacker square in the chest with a grenade. End of attacker.
My grandfather served in KMAG with a colonel who’d been in the Philippines during the Moro Campaigns and was nearly killed in just such a situation. The Moros would get hopped up on drugs (to make themselves fiercer and to deaden the pain), wrap several layers of jungle vine around their torsos to help absorb bullets, and charge American troops with machetes swinging. Colonel (then Lt) Fuller hit his attacker five times in the chest and the guy still managed to reach him and lay him open from right shoulder to left hip. As Fuller was going down, he fired his last round, which caught his attacker under the jaw, killing him.