Why did Private Pyle kill himself in Full Metal Jacket?

In what’s probably the most misunderstood in the film, Pvt. Pyle kills himself and Gunnery Sergeant because he’s a slow, dimwitted, and unstable man who has fully internalized all of his training and indoctrination.

He has taken Hartman’s demands that he become a killer with a hard heart and a pure killer instinct and acts on them. The first time we meet Pyle, it’s evident that he is slow and dimwitted. Rather than seeing him as trainable, Hartman immediately switches to violence to force him into obedience and compliance.

Unlike the other Marine recruits in his platoon, he’s too slow to know better and too simple to deal with the indoctrination. Pvt. Leonard Lawrence, a/k/a Gomer Pyle, or Private Pyle, is profoundly disturbed and of subnormal intelligence even when he arrives. He believes everything he is told, absolutely literally, including the Marine Rifle Creed (see below), unfortunately. Pyle is then massively traumatized by everything that has happened to him, becomes severely depressed, and eventually becomes dangerously suicidal. Pyle’s instability leads him to murder his superior and kill himself.

By the way, the subtext of the novel ‘Short-Timers’ and the film ‘Full Metal Jacket,’ based on that novel, is the genuine “Project 100,000.” This was a 1960s policy in which those with developmental disabilities, subnormal intelligence, severe personality disorders, etc., who would have previously been deemed unfit to serve, were drafted into service.

(Secretary of Defense Robert McNamara, the architect of Project 100,000. This project was a massive failure. The men who went through it had great difficulty following even the most straightforward orders, got themselves and their fellow sailors, soldiers, airmen, and Marines killed, and ended up living worse lives after the military than they had before – and despite veterans sometimes suffering effects from combat, the overwhelming majority live far better lives as a result of their time in the military.

Pyle is a classic case of a Project 100,000 recruit. He has an IQ south of 80; for context, an IQ of 80 is borderline deficient/low average. In the day, he would have been labeled ‘retarded’; today, we might have labeled him as having Asperger’s. He’s clearly on the spectrum and has a touch of the ’tism. Given his situation and the timeframe in which the story takes place, this has also made him very unstable. Pyle finds his match in a violent and sadistic Senior Drill Instructor (SDI), Gunnery Sergeant Hartman.

Hartman is incapable of training Pyle and never really tries that hard. He beats, mocks, and abuses Pyle relentlessly—these continued attempts to torment Pyle into compliance drives Pyle into a deeply suggestible state.

Hartman is beating a puppy, not realizing that beaten puppies grow up to be vicious dogs.

It should go without saying, but getting smacked around is not training. And taking this kind of abuse is not suitable for anyone, let alone someone like Pyle. No wonder then that he turns into a mad dog killer. Pyle, in the face of this unrelenting abuse and quite literally believing everything he is being told by his peers and by Hartman, becomes increasingly dangerous.

While this harsh training might be perfectly acceptable for regular Marines expected to face combat in relatively short order, one needs to understand that regular Marines have normal intellects. Some are even above average. This bar of average or above-average IQ is basically a necessity. Dumb Marines wouldn’t last long in combat, and the Marine Corps is exceptional about weeding out people of low intelligence and serious mental issues, no matter what sailors, soldiers, and even some Marines might say.

However, during Project 100,000, the Marines were stuck with men like Pyle, and this harsh training ratchets Pyle and other low-IQ soldiers up and makes them increasingly unstable. He begins to show genuine signs of severe mental instability, including talking to his rifle.

Unfortunately, these warning signs are also ignored because training during Vietnam wasn’t just harsh; it was also rushed. They needed men on the line fast, so corners were cut, and problem cases were ignored.
The USMC’s low standards during Prohect 100,000 is how Hartman gets away with all the violence against his men. Neither before nor after Vietnam was this tolerated – in fact, it’s a crime for a DI to assault his men. But it was put up with during Vietnam because, again, even the worst DI was better than no DI when you’re rushing civilians into combat.

Finally, Hartman decides using the memory of a Presidential assassin and a mass murderer is an excellent way to motivate men at the shooting range.

This would never have been an acceptable teaching method. Ever.

R. Lee Ermey, himself a Marine SDI in the mid-1960s, described Hartman as “a complete psycho” for many reasons. He hated the character and admitted he was made physically ill by delivering this dialogue about the assassination of JFK and the mass murder committed by Charles Whitman as good things done by former Marines.

No Marine Drill Instructor, even at the height of Vietnam, would have ever done so.

Filming this scene made R Lee Ermey want to vomit. I’m not joking. He insisted simply delivering these lines made him physically ill. After Hartman essentially condones a criminal conspiracy within his ranks to assault Pyle (blanket parties, though they do happen, are HIGHLY illegal; see Code Red and A Few Good Men for another example), Pyle finally changes his behavior and begins to comply, but by then, the total damage has been done, Pyle has already totally committed to his path of murder and suicide.

Ultimately, Pyle murders Hartman and kills himself.

“THIS IS MY RIFLE.
THERE ARE MANY LIKE IT BUT THIS ONE’S MINE.
MY RIFLE IS MY BEST FRIEND.
IT IS MY LIFE.
I MUST MASTER IT AS I MUST MASTER MY LIFE.
WITHOUT ME, MY RIFLE IS USELESS.
WITHOUT MY RIFLE, I AM USELESS.
I MUST FIRE MY RIFLE TRUE.
I MUST SHOOT STRAIGHTER THAN MY ENEMY WHO IS TRYING TO KILL ME.
I MUST SHOOT HIM BEFORE HE SHOOTS ME.
I WILL!
BEFORE GOD, I SWEAR THIS CREED.
MY RIFLE AND MYSELF ARE DEFENDERS OF MY COUNTRY.
WE ARE THE MASTERS OF OUR ENEMY.
WE ARE THE SURVIVORS OF MY LIFE.
SO BE IT, UNTIL THERE IS NO ENEMY, BUT PEACE.
AMEN!”

— USMC Rifleman’s Creed, Maj. Gen. William H Rupertus. 1907–1910 (National Guard), 1913–1945 (USMC 4th Marine Regiment, 1st Marine Division).