They Called It A Pea Shooter — Until It Deleted An Entire Regiment

The “Peashooter” That Turned a Jungle Into a Slaughterhouse

At 10:30 p.m. on October 24th, 1942, Sergeant Mitchell Paige crouched in a muddy foxhole on a blackened ridge of Guadalcanal and ran his hand over the cold steel breach of a weapon half the United States Marine Corps thought was a bad joke.

Rain hammered the island in heavy tropical sheets, turning the jungle floor into a soup of mud, blood, and rot. Two hundred yards to the south, the darkness was alive. You could hear it if you listened past the rain—the snapping of twigs, steel brushing against wood, low whispers from a thousand throats.

Out there in the black, the Japanese 2nd Division—the feared Sendai Division—was forming up.

They were the emperor’s elite jungle fighters. Undefeated. Battle‑hardened. Conditioned to kill and to die without hesitation. They had marched through hundreds of miles of tropical hell to reach this ridge.

Their orders were simple:
Break the Marine line.
Seize the airfield.
Drive the Americans into the sea.

Paige looked down at the “joke” sitting in the mud beside his machine guns.

The 37mm M3 anti‑tank gun.

To a civilian it might have looked like a cannon. To a professional soldier in 1942, it looked like a toy. The barrel was absurdly thin, barely thicker than a drainpipe. The wheels were small and spindly, like something off a farm cart. The whole thing sat low and unimpressive, as if embarrassed to be on the battlefield.

The infantry had names for it.

The peashooter.
The doorknocker.
The mosquito gun.

In North Africa and Europe, the war had already outgrown the 37mm. German armor kept getting thicker. When American gunners fired 37mm rounds at Panzers, the shells bounced off like thrown rocks. After‑action reports called it obsolete, underpowered, a waste of steel and shipping.

On paper, the verdict was final:
This gun was useless.

But on this night, on this ridge, under this rain, Mitchell Paige did not treat it like a punchline.

He treated it like the only thing standing between his men and extinction.

A Weapon Without a War

The 37mm M3 had been born for a different battlefield.

On a training range, against thin‑skinned vehicles and light armor, the little gun made sense. It was light, easy to tow, cheap to build. In the early days of the war, it seemed good enough.

Then the German tanks evolved, and the 37mm didn’t.

In the deserts of North Africa, American crews watched their shells spark and ricochet off armor that might as well have been a bank vault door. The gun that was supposed to kill tanks could do nothing but make them angry.

Washington read the reports and moved on. Bigger guns. Heavier calibers. Real tank killers.

The 37mm was being phased out.

But the Marine Corps doesn’t throw much away. When the 1st Marine Division loaded up for the assault on Guadalcanal, they took everything that could be made to fire—including the despised 37mm.

The gun crews knew what the riflemen thought of them. They heard the snickers on the beach as they dragged the 900‑pound guns through the soft sand. It didn’t feel like being issued a weapon; it felt like being given a burden. A joke. A dead weight.

The jungle made it worse.

Guadalcanal wasn’t just a battlefield; it was an organism designed to destroy human beings. The heat pressed down like a wet wool blanket. The mud sucked at boots and wheels like a living thing. Moving a rifleman was hard. Moving a 900‑pound cannon was torture.

The gunners became draft animals. They looped straps over their shoulders and hauled the guns through waist‑deep swamps. They clawed their way up ridgelines so steep they had to dig their fingers into the soil just to hold on. Every yard hurt.

And from the foxholes on either side, infantrymen laughed.

What are you going to do with that thing in this jungle?
Hunt squirrels?
Shoot bamboo?

On a map, they were right. Visibility on Guadalcanal was 20 feet on a good day. Trees grew so tight a man had to turn sideways to move between them. There were no tank duels here. No long‑range gunfights.

There were no Japanese tanks at all.

According to the experts, the 37mm had no business on that ridge.

The experts had made one critical mistake:

They were still thinking of it as an anti‑tank gun.

Turning a Joke Into a Giant Shotgun

Paige and the gun crews weren’t thinking about armor penetration charts or muzzle energy. They were thinking about the one thing the Japanese did better than anyone else in the Pacific:

Human waves.

The banzai charge was simple and horrifying. Thousands of men, often at night, fixed bayonets and sprinted straight into the American line, screaming, firing from the hip, climbing over their own dead.

Against that, a rifle was too slow. A machine gun was deadly—but barrels overheated, belts jammed, gunners were shot.

You didn’t need finesse. You needed brutality. Volume. A way to erase men, not just kill them.

So the gun crews started looking at what they had.

Armor‑piercing rounds? Useless—no tanks.
High‑explosive? Limited.
And then, at the bottom of a forgotten crate, they found something nobody had cared about in the manuals:

Canister M2.

On paper, it was just a “brush and wire clearing” round. In reality, it was something far nastier.

If a shotgun shell is a plastic tube filled with pellets, the M2 canister round was that concept turned into an industrial nightmare. A thin metal cylinder the size of a man’s forearm, packed with 122 steel balls, each nearly half an inch across.

Fire it, and the casing disintegrated just outside the barrel. The balls spread into a widening cone of supersonic metal.

At 100 yards, it could sweep a jungle trail clean. At 200 yards, it became a steel storm no human body could endure.

The 37mm M3 wasn’t a tank gun anymore.

It was a giant sawed‑off shotgun.

But to use it the way the situation demanded, the crews had to make a choice that bordered on suicidal.

They unbolted the heavy steel shields from the fronts of their guns.

The shields were there for a reason: to catch bullets and shrapnel aimed at the crew. Removing them stripped hundreds of pounds off the weapon—and stripped away the only real protection the gunners had.

Now they were completely exposed.

But without the shield, the gun balanced beautifully. One man could grab the trails and whip the barrel left or right in a heartbeat.

They weren’t building a bunker gun.

They were building a close‑quarters slaughter machine.

The Night the Jungle Stopped Breathing

Around 11:00 p.m., the Japanese sent their first probe. Not the main attack—just a hand in the dark, feeling for the Marine line.

A machine gunner saw movement and opened up. Tracers stitched through the rain. Japanese rifles barked back. A Nambu light machine gun chattered from the tree line.

Then a squad of Japanese soldiers broke from the jungle, sprinting, bayonets fixed, heading straight for a gap between the Marine machine guns. Exactly the sort of hole a banzai charge could pour through.

Fifty yards. Forty.

They had found the seam. They thought they were in the clear.

The crew on the nearest 37mm didn’t bother with the sights. The gunner simply looked over the barrel, swung the naked gun like a fire hose, and shouted.

The loader slammed a canister round home.

The gunner stomped the pedal.

The sound was not a rifle crack or a machine gun’s rhythm. It was a single, deep, concussive roar that shook leaves loose from branches.

A tongue of flame spat from the muzzle.

The shell burst. One hundred twenty‑two steel balls screamed into the dark at 2,000 feet per second.

They didn’t hit a man.

They hit everything.

One second, the charging squad existed—screaming, running shapes in the rain.

The next second, they were gone.

Vegetation shredded. Grass turned to mist. Bodies simply came apart. It looked less like men being shot and more like a piece of the night being erased.

In the surrounding foxholes, Marines who had spent weeks mocking the “peashooter” fell silent.

A machine gun kills men in a line.

The 37mm with canister deleted an entire piece of the world.

Six Hours in Hell

The Japanese understood immediately that something was very wrong.

Their probing attack was not just repelled—it was annihilated.

General Maruyama didn’t call off his main assault.

He ordered it intensified.

Within minutes, heavy weapons began zeroing in on the 37mm muzzle flashes. Mortar shells walked up the ridge. Rifle fire poured toward the exposed crews.

Then the horn sounded.

A long, rising wail cut through the rain. Hundreds, then thousands of voices answered:

“BANZAI! BANZAI! BANZAI!”

They hit like a tidal wave of flesh and steel.

Marine machine guns poured streams of red tracers into the oncoming mass. Men fell, but the line didn’t slow. More bodies, more bayonets, more screams.

At 100 yards, the 37mm guns fired.

At 80 yards, they fired again.

Boom—clack. Boom—clack. Boom—clack.

Load, fire, eject.
Load, fire, eject.

Every round was a storm of steel. The canister shot carved swaths through the charging formations like a scythe through tall grass. Where the guns pointed, men simply stopped existing. Bodies were hurled backwards, torn apart, lifted off their feet by multiple impacts.

But there were always more.

For every ten men shredded, twenty more appeared out of the darkness.

The Japanese began aiming directly at the gun crews. Bullets pinged off wheels. Grenades exploded in the muck around the trails. A loader went down with a bullet in his shoulder; another Marine dove into the pit to take his place, slipping on the mountain of hot brass piling around the wheels.

The barrels glowed. Paint blistered and burned away. The recoil systems hammered so violently that the guns dug themselves deeper into the mud with every shot. Water splashed up, hissed into steam upon touching the red‑hot steel, wrapping the crews in a ghostly fog that smelled like boiling oil and blood.

They were firing beyond the design limits. The manuals said 25 rounds per minute.

They were pushing 30, 35.

If they stopped, the line would break.
If the line broke, men died.

So they didn’t stop.

When the “Useless” Gun Saved an Army

Eventually, the price for stripping off the shields came due.

A Japanese suicide team crawled through a drainage ditch under the arcs of machine gun fire and popped up 20 yards from one of the guns. Three grenades landed in the mud around the wheels.

A blast, a scream, and the number two gun went silent—crew dead, carriage smashed, barrel pointing uselessly at the stars.

The gap opened. The Japanese felt it instantly and surged toward it.

This is where most lines collapse.

Sergeant Mitchell Paige didn’t let it.

He grabbed his machine gun, sprinted through a world made of explosions and screams, and threw himself into the dead gun’s position. Alone, without a loader, he set up and opened fire at point‑blank range, sweeping the gap, screaming curses into the dark.

He was one man trying to fill the hole left by a cannon.

Back at the remaining 37mm, the last crates of canister emptied. The loader reached into the box and found wood. Nothing left. No more steel storms. Just empty brass carpeting the pit.

They scavenged whatever they could find. A runner came in carrying a crate—armor‑piercing rounds. Solid slugs. Useless for stopping a massed human charge.

“Load it anyway.”

The gunner didn’t aim at chests. He aimed at the ground.

The 37mm slug hit volcanic soil at 2,000 feet per second and shattered rock into a cloud of jagged fragments. The earth itself exploded into a spray of lethal shrapnel.

It wasn’t as effective as canister. But it was violence. It was something. And something meant seconds.

Seconds until reserves could arrive. Seconds until the Japanese finally started to falter.

By dawn, the ridge had been fought over at arm’s length. Men had killed each other with rifle butts, shovels, fists, and knives. The last Japanese pushes had stalled in a mess of bodies and broken weapons.

When the first light of October 25th crept over Guadalcanal, the Marines finally saw what they had done.

The jungle in front of the 37mm positions was gone. Trees stripped bare and splintered. Tall grass mowed flat. For 200 yards, the ridge looked like it had been blasted by a hurricane made of steel.

The ground was carpeted with bodies—over 2,000 Japanese dead, stacked three and four deep in front of the guns. The closest corpses lay just feet from the 37mm wheels.

They had made it that far.

They had gone no farther.

The “peashooters” had not just held the line.

They had turned the finest infantry of the Japanese Empire into mulch.

The Weapon the War Forgot

When General Alexander Vandegrift and other senior officers walked the ridge later that morning, they stepped ankle‑deep through empty brass. The 37mm barrels were burned bare metal, recoil springs cooked, tires shredded.

On a technical inspection, the guns were wrecks.

On a strategic inspection, they were something else:

The reason the Japanese were not standing on Henderson Field.

The 37mm had not failed.

The doctrine had.

The manuals called it a tank gun. The engineers called it obsolete. The infantry called it useless.

The Marines on Guadalcanal called it something else:

The best friend they ever had.

For the rest of the campaign, every commander wanted a 37mm with canister on his flank. The once‑mocked gun crews suddenly found riflemen volunteering to haul their ammunition and dig their foxholes.

And then, just as quickly, the war moved on.

Bigger guns. Better tanks. Bazookas. Flamethrowers.

The little 37mm M3 faded into scrap piles, storage yards, museum corners—another obsolete tool in a war obsessed with bigger, faster, newer.

Sergeant Mitchell Paige went home, wore his Medal of Honor, lived his life. But part of him stayed on that ridge, in the rain and the steam, listening to the roar of a “useless” gun that refused to be useless.

The story of the 37mm isn’t about a perfect weapon.

It’s about what happens when desperate men ignore experts, ignore doctrine, and ask one simple question in the dark:

“How can we make this kill?”

On one night in 1942, a toy cannon and a crate of canister rounds answered that question so brutally that an entire division died learning the lesson.

Sometimes the weapon that changes everything is not the one designed for the job.

It’s the one someone refused to give up on.