Snipers generally fire one shot at a time from bolt-action weapons that provide greater accuracy and distance but leave them virtually defenseless against automatic weapons at close range.
In Vietnam, the enemy put a bounty on the head of U.S. snipers. Mawhinney carried a sidearm with a round he could fire into his temple rather than be captured.
Although he winces at comparisons, Mawhinney's numbers place him in the same category as famed snipers of the past: Russians and Germans at the battle of Stalingrad, British and Germans during the trench warfare of World War I, Marines and their Japanese enemy during the savage island campaigns of World War II.
"Chuck was extremely aggressive," said retired Master Gunnery Sgt. Mark Limpic, Mawhinney's squad leader. "He could run a half-mile, stand straight up and shoot offhand and drop somebody at 700 yards. I had a lot of guys who did nothing but bellyache, but Chuck never complained."
Learning to Hunt Early
Although his father had been a combat Marine in World War II, Mawhinney planned to join the Navy after graduating in June 1967 from high school in the backwoods town of Lakeview, Ore.
But the Marine recruiter made him an offer he could not resist: You can delay boot camp until after deer hunting season.
"Kind of ironic, given where I went and what I did," Mawhinney said.
Mawhinney had learned to hunt early. "When I was a kid, anything that crawled or flew was fair game."
An expert marksman in boot camp, he was sent to sniper school at Camp Pendleton. At graduation he received a little red book that purported to be the complete sniper's manual. Inside was a single admonition: Thou Shalt Kill.
He shipped out to Vietnam during the heavy fighting that followed the Tet Offensive in early 1968. As a sniper, Mawhinney had an uncanny ability to gauge distance, moisture, weather and terrain--factors that determine how much a bullet will rise or drop during flight. He had the patience to wait hours for the right shot. He was scared but exhilarated.
"Normally I would shoot and run, but if I had them at a [long] distance, I wasn't worried," Mawhinney said. "I would shoot and then lay there and wait and wait and wait and pretty soon somebody else would start moving toward the body. Then I would shoot again.
"When you fire, your senses start going into overtime: eyes, ears, smell, everything," he said. "Your vision widens out so you see everything, and you can smell things like you can't at other times. My rules of engagement were simple: If they had a weapon, they were going down. Except for an NVA paymaster I hit at 900 yards, everyone I killed had a weapon."
Near the An Hoa base outside Da Nang, he caught a platoon of North Vietnamese Army regulars crossing a stream. He hit 16 with head shots with an M-14, which he often carried in addition to his bolt-action.
The 16 were listed only as probable kills because no officer was there to see their lifeless bodies float by and there was no chance to search the bodies.
He retains an intimate knowledge of what people look like in the throes of death.
"Sometimes, depending on where they're hit, they'll just drop and not move," Mawhinney said. "Nobody dies the same, and I've seen it all. I did a lot of mercy-shooting. I wounded people and then cranked another round into them. I didn't want them crawling around out there."
From the relative safety of the combat base, Mawhinney and his sniper team partner would venture forth daily into the bush.
Drenched by heat and humidity, sometimes they would stalk the enemy for hours until they could get into range for one or more shots. Other times, they would set up in areas where they knew the enemy would soon be traversing and then remain silent and motionless for hours.
"You get to the point where you start living like an animal," Mawhinney said. "You act like an animal, you work like an animal, you are an animal. All you think about is killing."
In the sniper teams an experienced marksman would be paired with a rookie, who manned the binoculars and an automatic weapon for cover fire. The sniper decided when the rookie was ready for his first kill.
Mawhinney trained half a dozen snipers and tried to make sure it was a "confidence shot," an easy target from about 300 yards. He said he gave all of them the same lecture he had received after his first kill:
"That wasn't a man you just killed; it was an enemy. This is our job. This is what war is all about. You screw up, you die."
It was not, by any stretch, a game.
When an overeager platoon leader posted a "kill board" for snipers, Mawhinney objected.
"It started making a competition out of it," he said. "Some of these young kids wanted to get kills so they were taking chances with their lives. We talked to the squad leader, the platoon sergeant and the [commanding officer], and said 'This is B.S. Take this board down.' "