The US Marine Corps' deadliest sniper might never have become one if it weren't for a wild night of drinking and a fake toothache, new book reveals

• The deadliest sniper in Marine Corps history is Charles "Chuck" Mawhinney.
• During the Vietnam War, he had 103 confirmed kills and 216 probable kills over 16 months in country.

Chuck Mawhinney is a legend for the death he dealt in Vietnam as a sniper protecting his fellow Marines, but he might never have become one if it hadn't been for getting blackout drunk at the worst possible time and, later, faking a toothache to score a chance to join a sniper team, a new book has revealed.

With 103 confirmed kills and hundreds more probable, Mawhinney is the deadliest sniper in Marine Corps history, a fact that ruffled some feathers when it first came to light decades after the end of the Vietnam War.

Jim Lindsay's "The Sniper," the first biography to explore Mawhinney's life and experiences in and out of war with his input, tells the story of a wild young man who found his calling in a horrible conflict he would later try, unsuccessfully, to leave behind. Though he has accepted his service and fame, some of the nightmares have never quite gone away.

Mawhinney made his name as a scout sniper and skilled marksman, but that wasn't what he wanted when he joined the Marines, like his father before him, the book suggests. What he really wanted to do was fly.

He loved shooting and had a talent for it from a young age, but when he considered enlistment, he asked if he could be a pilot. The recruiter said: "If you sign up for four years, I can guarantee you'll be in aviation. Whether or not you fly is up to you."

Mawhinney signed up with the Marines on the spot and then immediately headed off to talk to the local authorities about tossing his criminal records, specifically a file cabinet full of minor-in-possession offenses, remnants of times in his younger years involving too much booze.

The authorities agreed to clean out his records after confirming he'd actually joined the Marines, clearing the way for him to enlist without problem.

But even as a Marine, Mawhinney couldn't completely shake his reckless behavior, and a night of drinking cost him his chance to be an aviator. But it did open the door to becoming a sniper.

The night before an 8 a.m. exam to qualify for aviation training, Mawhinney's friends invited him to get tattoos. He thought that was silly given that none of them had seen combat but went with them and joined his friends when they got drinks for a little liquid courage.

Next thing he knew, he woke up in a movie theater at 5 a.m., the only one of his friends to have actually gotten a tattoo.

When he got back to base for the qualification test, he failed it, meaning he'd have to wait another month to try again. In that waiting period though, he learned about a new program that hadn't existed when the US first entered the Vietnam War: the Marine Corps Scout Sniper program.

"He loved shooting rifles more than being a pilot, so he entered," Lindsay, a long-time friend of the marksman, explained in his new book.

Mawhinney qualified for entry into the Marine scout sniper course because he'd already earned distinction as an expert marksman. In the program, he trained with his first sniper rifle, a Remington 700 with 3—9x Redfield scope, learned to record critical data on previous engagements (DOPE), and learned the ins and outs of camouflage, how to navigate anytime day or night, and how to find booby traps.

He earned his scout sniper MOS, or military occupational specialty, 8541. And not long after, he headed off to war.

When he arrived in Vietnam, an officer yelled out: "Chuck Mawhinney! MOS 0311, rifleman! Lima 3/5." When he attempted to correct the officer, they said "the Corps doesn't need snipers! It needs grunts!" He then received an M16 rifle that he hated immensely and that jammed in combat.

After his first real firefight, during which he took control of an M60 machine gun after two gunners fell, he was informed that he would be a new machine gunner, a position he did not want anymore than he wanted his M16.

"Though he'd be rid of the M16, he knew the life expectancy of a machine gunner was short," Lindsay wrote. "Chuck tried to trade off the big gun but there were no takers."

In the middle of this particular dilemma, Mawhinney learned that a Marine sniper with Lima 3/5 needed a spotter. All he needed was a reason to go to An Hoa to put in a request.

Mawhinney faked a toothache, and when he got to the base, he walked past the dentist and hunted down the sniper platoon leader instead.

He managed to convince him to let him join a sniper team as a spotter, a supporting role he would serve in to learn the tricks of the trade in a real warfighting environment before becoming a sniper. Spotters at that time supported snipers by scanning for targets, covering, and confirming hits and kill shots, among other battlefield tasks.

At the armorer's station, where Mawhinney received the M14 rifle that the spotters carried, he handed over his defective M16 and said: "Throw away this son of a bitch. It's never been any good and it never will be."

Mawhinney was only a spotter for a short time before he was made sniper team leader and given a new Remington 700 with .308 ammo. With this weapon, the military version of which is known as an M40, he would do more damage to the enemy than some companies.

In his most famous engagement, he killed 16 enemy fighters in just 30 seconds with 16 head shots with his spotter's M14, stopping a nighttime river crossing by North Vietnamese troops and an assault on the Delta 1/5 position.

After Mawhinney and his spotter violently blunted what might otherwise have been a devastating assault, the pair quickly fell back and departed the scene amid continued small arms and machine gun fire, and, as Lindsay tells it in his book, "pith helmets and bodies floated down the river."

When he eventually left the Marine Corps, Mawhinney did so with a Bronze Star Medal with Combat Valor, Navy Achievement Medal, Navy Commendation Medal with Combat Valor, and a pair of Purple Hearts.

It would, however, be another two decades until the public became aware of the sniper's unparalleled successes in combat.