November 18th, 1944.
427 hours.
Buganville Island.
Corporal James Mitchell, 23 years old, Massachusetts native, lies in a hastily dug foxhole on Hill 260, watching the jungle treeine 200 yd down slope.
His hands shake, not from fear, though there’s plenty of that, but from the weight of what sits beside him.
A modified Browning automatic rifle, M1918 A2.
Except this one has something different, something the brass swore would change everything.
The pre-dawn darkness carries sounds, rustling, movement, the kind that makes your stomach knot because you know what’s coming.
Mitchell’s unit, Baker Company, Third Marine Division, has held this position for 6 days.
Every night, the Japanese come.
Every night, his bar runs dry at the worst possible moment.
20 rounds.
That’s all the magazine holds.
20 rounds against wave attacks of 50, 60, sometimes 100 men screaming up the slope.
But tonight’s different.
Tonight, his bar has a modified feed system.
Tonight, every fifth round isn’t a standard 3006 cartridge.
Tonight, every fifth round carries an M2 explosive primer, the same charge used in 40 mm grenades, crimped into a specially reinforced case.
The rustling stops.
Mitchell’s finger finds the trigger.
His squad leader, Sergeant Davis, is three foxholes over.
They’ve practiced this.
They know the theory, but theory and a nighttime bonsai charge are different things entirely.
Then the screaming starts.
By November 1944, the Pacific War had revealed a critical problem with American infantry firepower.
The Browning automatic rifle, the BAR, was the squad’s primary automatic weapon.
Designed by John Moses Browning in 1917, adopted in 1918, it fired the powerful 306 Springfield cartridge.
At 19.4 lb loaded, it delivered devastating firepower.
But it had one fatal flaw in Pacific combat.
Magazine capacity.
20 rounds.
That’s what the standard bar magazine held.
20 rounds in a weapon designed to provide sustained suppressive fire.
20 rounds when Japanese infantry doctrine emphasized overwhelming night assaults with numerical superiority.
On Guadal Canal in 1942, on Terawa in 1943, on Saipan and Pleu in 1944, American units reported the same problem.
Bay gunners would fire their magazines empty in 4-second bursts, then fumble for replacements while enemy soldiers close the distance.
The statistics were sobering.
On Tarawa, November 1943, the Second Marine Division suffered 3,47 casualties in 76 hours.
Afteraction reports cited bar magazine changes as a critical vulnerability during Japanese counterattacks.
At Pleu, September 1944, the First Marine Division recorded 57 instances where bar gunners were killed or wounded during magazine changes.
The weapon’s cyclic rate of 5650 rounds per minute meant a 20 round magazine lasted 2.4 seconds of continuous fire.
The Marines needed sustained firepower.
They needed something that could break up mass charges without leaving gunners vulnerable during reloads.
But increasing magazine capacity wasn’t simple.
The Bay’s bottom loading magazine design was integral to the weapon.
Larger magazines would be heavier, more prone to feed failures in jungle conditions, and incompatible with prone firing positions.
The solution came from an unexpected source.
In July 1944, Captain Theodore Walsh, Ordinance Corps, stationed at Aberdine Proving Ground, Maryland, was reviewing declassified German weapons research.
The Germans had experimented with explosive ammunition for aircraft weapons, rounds that detonated on impact or near miss to increase effectiveness against bombers.
Walsh saw something different.
What if you could make standard ammunition do more damage without changing the basic cartridge? He requisitioned 500 M2 explosive primers, typically used in 40 million grenade launchers and a workshop at Aberdine.
The M2 primer contained 96 mg of RDX explosive, enough to detonate the main charge in a 40 molino projectile.
Walsh theorized that crimping these primers into reinforced306 cartridge cases would create rounds that exploded on impact, multiplying the bars effectiveness without requiring new weapons or training.
The initial tests on August 3rd, 1944 were promising.
Standard 306 armor-piercing rounds penetrated ballistic gelatin targets with minimal cavitation.
The explosive primer rounds created cavitation channels four times larger with secondary fragmentation effects.
More importantly, when fired at wooden barriers simulating jungle vegetation, the explosive rounds cleared significantly more foliage.
But there was a problem.
The explosive primers generated 18% more chamber pressure than standard rounds.
Firing them continuously risked barrel failure.
Walsh’s solution was elegant.
Load them every fifth round.
Four standard rounds to maintain reliable feeding and manageable recoil.
One explosive round to multiply effect.
The pattern created a predictable rhythm.
Suppressive fire with standard rounds, devastating impact with explosive rounds, all from the same magazine.
By September 15th, 1944, Aberdine had produced 50,000 modified cartridges designated 3006 M2 high explosive.
The cartridge cases were reinforced at the base, marked with a single red band for identification.
The ordinance department classified the project secret and assigned it to commac commander special weapons Pacific, a littleknown logistics command responsible for evaluating experimental ordinance in combat conditions.
The first shipment reached Guadal Canal on October 8th, 1944.
6,000 rounds, enough to equip one company of Marines with modified bar loads for field testing.
Baker Company, Third Marine Division, was selected.
They were heading to Bugenville, where Japanese forces still held significant territory, and night attacks were constant.
The Marines called them hot rounds or snappers because of the distinctive crack they made on impact.
The official designation was too cumbersome for combat use.
What they didn’t know was what the Japanese would call them.
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This story stayed buried in classified files for 35 years, and you’re about to find out why.
Back to Jimmy Mitchell.
The 306 M2 high explosive round looked almost identical to standard ammunition.
Length 3.34 in.
Case diameter 473 in.
Projectile weight 150 grains, the same as M2 armorpiercing rounds.
The only visible difference was the red band painted around the cartridge case 1/4 in from the base.
Inside, the differences were substantial.
The cartridge case was manufactured from manganese bronze alloy instead of standard brass, giving it 40% greater tensile strength to handle the explosive primer’s pressure spike.
The case wall thickness at the base measured 0025 in versus 008 in for standard cases.
This reinforcement added 12 grains to the total cartridge weight, barely noticeable when loaded in a magazine.
The M2 explosive primer sat in a specially machined primer pocket, deeper than standard to accommodate the primer’s greater length.
The primer contained 96 mg of RDX explosive cycllotromethyl nitri nitraine, the same compound used in composition C3 plastic explosive.
This was significantly more energetic than the standard boxer primer’s 4 mg of lead stifanate.
When the firing pin struck the primer, the RDX detonated with approximately 18400 ft per second prisons.
the shattering effect of an explosive.
This detonation served two functions.
First, it ignited the 47 grains of IMR 4895 propellant powder, driving the projectile down the barrel at 2,700 ft pers.
Second, it transmitted a shock wave through the propellant, ensuring more complete combustion and thus higher muzzle velocity.
The projectile itself was modified.
The standard M2 armor-piercing round had a hardened steel core.
The M2H round used a mild steel core surrounded by a copper jacket with the forward section containing a small cavity filled with eight grains of additional RDX.
Upon impact, the deceleration force triggered this charge, causing the projectile to fragment into 15 to 20 pieces rather than remaining intact.
Think of it this way.
A standard 30 BO6 round is like a nail driven through wood.
It makes a hole.
The Mtus H round is like a small firecracker that goes off after it punches through.
It makes a hole, then explodes inside, creating multiple wound channels and clearing vegetation in a small radius.
The pressure spike from the explosive primer was the critical engineering challenge.
peak chamber pressure in a standard Bong 3006 firing measures approximately 50,000 PSI.
The M2 he rounded generated 58,000 PSI.
This was within the bar’s design tolerance of 65,000 PSI, but prolonged firing could accelerate barrel wear.
Aberdine’s testing showed that firing M2 he rounds continuously could reduce barrel life from 10,000 rounds to 6,500 rounds.
The five round spacing solved this.
Four standard rounds at 50,000 PSI, one M2HE at 58,000 PSI, averaging 51,600 PSI over five rounds, well within safe operating parameters.
The spacing also helped with recoil management.
The M2 round produced 22% more recoil energy than standard ammunition.
Firing them continuously would make the bar nearly uncontrollable in automatic fire.
The four round spacing meant the shooter could anticipate the harder kicking round and maintain aim.
The ammunition was packaged in standard 20 round bar magazines preloaded at Aberdeene with the correct spacing.
Each magazine contained 16 standard M2 ball rounds and four M2H rounds in the fifth, 10th, 15th, and 20th positions.
The magazines were marked with yellow tape on the base plate for identification.
Sergeants in Baker Company received the shipment on November 12th, 1944 at their staging area on Bugganville.
They were given minimal instruction.
Load these magazines, fire normally, expect slightly increased muzzle flash, and report.
The classification meant they couldn’t discuss the ammunition with anyone outside their unit.
They didn’t know what the rounds would do beyond increased effect on target.
Jimmy Mitchell got his first yellow taped magazine on November 13th.
He loaded it into his bar in the armory tent, ejected it, loaded it again.
The rounds looked normal except for the red bands.
They felt normal.
The magazine weight was identical to standard loads.
He asked Sergeant Davis, “What made them special?” Davis shrugged.
“Guess we’ll find out when we shoot somebody with them.” 5 days later, they found out.
428 hours.
November 18th, 1944.
Mitchell sees them now, shadows becoming shapes.
The Japanese are using their standard approach, loose formation, moving through the jungle, using every bit of cover, trying to get within grenade range before the final rush.
He counts 8, 12, 20.
They keep coming.
His bar is set to automatic.
Selector switch all the way forward.
Bipod legs deployed.
The weapon angles down the slope, tracking the movement 180 yards out.
Sergeant Davis doesn’t give an order.
Doesn’t need to.
Every Marine on the line knows the drill.
Wait until they’re close enough that you can’t miss.
Wait until they commit to the charge.
Then break them.
150 yards.
The shapes are clearly men now, moving faster.
The rustling becomes crashing.
Someone yells in Japanese.
125 yds.
Mitchell’s finger tightens on the trigger.
The bar’s fortock is slick with morning condensation.
His breathing steadies.
He picks a target.
Leading man moving straight up the trail.
100 yards.
The Japanese scream.
It’s not a war cry.
It’s a signal.
The scattered formation converges into a mass charge.
40 men, maybe 50, screaming and running uphill directly at Baker Company’s position.
Mitchell fires.
The bar hammers.
Four rounds punch out in a 3second burst.
Standard M2 ball.
He sees impacts on the leading man’s torso.
The soldier goes down.
Mitchell adjusts left.
Fires again.
Four more rounds.
Then the fifth.
The M2 H round hits a Japanese soldier center mass at 95 yd.
The impact looks different.
There’s a flash, small, orange, barely visible in pre-dawn light.
The soldier doesn’t just fall.
He’s thrown backward, arms spread as if punched by an invisible fist.
The men on either side of him flinch, stumble, one goes down with fragmentation wounds.
Mitchell doesn’t have time to process this.
He’s firing.
The bar cycles four standard rounds into the mass of charging infantry.
Then another M2H.
This one hits a soldier in the shoulder.
The flash is brighter.
The soldier’s arm separates.
Two men behind him scream.
The charge hesitates.
Waivers.
These are experienced Japanese infantrymen.
They’ve faced bar fire before.
They know the sound, the rhythm, the pattern.
This is different.
Their men aren’t just falling.
They’re being torn apart.
The spacing of the explosive rounds is random from their perspective.
Every few seconds, someone detonates.
Mitchell’s magazine runs dry at 429 hours.
He’s fired 20 rounds in approximately 8 seconds.
He drops the empty magazine, reaches for a fresh one.
Yellow tape on the base plate, slams it home, charges the weapon, resumes firing.
The entire marine line is shooting now.
Rifle fire, grenades, mortars landing in the jungle behind the Japanese formation.
But Mitchell can see his rounds working.
Each M2 he impact creates a small clear space.
Vegetation shreds.
Men fall in groups rather than individually.
His second magazine empties.
He reloads.
The Japanese charge has broken.
They’re falling back, dragging wounded, leaving bodies.
He fires into the retreating formation.
Controlled bursts.
Four rounds.
Fifth round impacts a tree trunk.
The explosive charge detonates, showering bark and splinters.
Two Japanese soldiers stumble, faces bloodied.
By 4:32 hours, the attack is over.
4 minutes from first shot to silence.
Mitchell’s hands shake violently now.
Adrenaline dump.
He’s fired three magazines, 60 rounds total.
12 of them were M2H.
He looks down slope.
The results are visible even in poor light.
Bodies lie in small craters.
Vegetation is cleared in spots as if something exploded, which it did.
The visual effect is disproportionate to the actual explosive force, but in the chaos of night combat, it looks devastating.
Sergeant Davis moves along the line.
Anybody hit? Nobody.
Baker Company took no casualties.
In previous attacks on Hill 260, they’d averaged three wounded per engagement.
This time, zero.
Davis stops at Mitchell’s foxhole, looks at the empty magazines, looks down slope, looks at Mitchell.
What the hell was in those rounds? Mitchell doesn’t know, but he knows it worked.
At 6:30 hours after dawn, a patrol moves down slope to assess enemy casualties and collect intelligence.
They count 23 Japanese dead, but the wounds are strange.
Entry wounds show massive cavitation.
Several bodies show fragmentation damage inconsistent with grenade or mortar fire.
One soldier’s rifle is bent.
The wooden stock shattered as if something exploded next to it.
The patrol’s coreman, Navy hospitalman Second Class Robert Chen, examines the bodies.
He’s seen thousands of gunshot wounds.
These are different.
He finds copper jacket fragments and small amounts of explosive residue.
He reports this to the company commander, Captain William Hayes.
Hayes forwards the report up the chain.
By 14 s hours, an ordinance officer from commac arrives via observation plane.
He examines the battlefield.
He examines Mitchell’s bar.
barrel shows accelerated wear, but remains serviceable.
He collects the empty magazines.
He confiscates Chen’s report and classifies it secret.
He tells Captain Hayes to continue using the ammunition and submit daily reports.
He tells the men to tell nobody outside the unit.
He flies back to Guadal Canal.
What Hayes doesn’t know, what nobody in Baker Company knows, is that 40 mi west, a captured Japanese soldier is being interrogated.
He’s from a unit that attacked American positions near Cape Tookina 2 days prior.
He describes a new American weapon.
He doesn’t know what it is, but his unit has a name for it, Kamari Jew, Thunder Rifle.
The Americans translate it as Thunderbeast.
By November 25th, 1944, Baker Company had expended 4,200 of their $6,000 in ME2 he rounds.
Their combat reports documented 17 engagements involving the modified ammunition.
Enemy casualties in these engagements totaled 147 confirmed dead versus 32 confirmed dead in engagements using standard ammunition.
More significantly, American casualties dropped.
Premhe, Baker Company averaged 2.3 casualties per engagement.
Post M2 he 0.8 casualties per engagement.
The statistics convinced Commac.
On December 2nd, 1944, they requested immediate production of 500,000 rounds from Aberdine proving ground.
They also requested expansion of the program to include306 ammunition for the M1 Garand rifle, though this proved technically unfeasible due to the Garand’s gas operated system being sensitive to pressure spikes.
Aberdine responded that maximum production capacity was 50,000 rounds per month.
The manganese bronze cases required specialized manufacturing.
The RDX filling process was labor intensive.
The Army couldn’t produce enough to supply standard infantry units across the Pacific theater, but they could supply specialist units.
Between December 1944 and August 1945, M2 ammunition was issued to approximately 2,400 Marines in specialized defensive and raiding roles.
This included three companies of the third marine division on Buganville, 840 rounds per company.
Two companies of the first marine division on Pleu, 840 rounds per company.
Four marine raider battalions conducting operations in the Philippines, 200 rounds per battalion.
Selected perimeter defense units on Guam, Saipan, and Tinian, variable amounts.
The ammunition never received an official nickname.
Hot rounds and snappers were common.
Thunder rounds emerged after Japanese prisoners used the term Kamari Jew.
But within the small community of Marines who used them, they were simply red bands after the identifying mark on the cartridge case.
The Japanese response evolved rapidly.
By January 1945, intelligence intercepts showed Japanese units discussing explosive bullets being used by American forces.
Japanese propaganda claimed this violated the HEG convention prohibition on explosive projectiles under 400 g.
A claim technically incorrect as the convention specified projectiles weighing below 400 g designed solely for explosion.
Whereas the M2H was a conventional bullet with enhanced fragmentation.
More practically, the Japanese adjusted tactics.
Night attacks became more dispersed.
Charges were abandoned in favor of infiltration.
Where possible, Japanese units avoided engaging American positions known to have thunder rifles.
This was precisely the psychological effect commac wanted, but logistics remained challenging.
The red banded cartridges required careful handling.
Dropping a loaded magazine could potentially detonate the primers.
The rounds couldn’t be stored in temperatures above 110° fire due to RDX stability concerns difficult in the Pacific theater and barrel wear became significant.
Bars firing M2 H ammunition regularly required barrel replacement after 4,000 rounds instead of the standard 8,000.
Staff Sergeant Michael Rodriguez, Baker Company’s armorer, maintained records showing 14 barrel replacements between November 1944 and March 1945, compared to a pre-war average of three Y4 per year.
The modified ammunition was consuming weapons faster than standard combat use.
On February 19th, 1945, Marines landed on Ewima.
Four companies carried M2 ammunition.
approximately 3,200 rounds total.
The volcanic ash and sand of Ewoima proved disastrous for the sensitive ammunition.
Feed failures increased.
Several rounds detonated in chambers due to overheating from sustained combat.
Two bars were damaged beyond field repair.
The Ewima experience prompted a critical assessment.
On March 10th, 1945, comspec way recommended restricting M2HUS to garrison and defensive positions where environmental conditions could be controlled.
Offensive operations in harsh terrain were too unpredictable.
This recommendation arrived simultaneously with planning for Operation Olympic.
The invasion of Cushu scheduled for November 1945.
Estimates projected 500,000 American casualties.
The joint chiefs were considering every possible advantage.
On July 15th, 1945, Aberdine received orders to increase M2 he production to 200,000 rounds per month by October.
This would require expansion of manufacturing facilities, recruiting additional workers, and prioritizing manganese bronze allocation.
The program was designated project thunder and given high priority.
Then on August the 6th and 9th, 1945, atomic bombs fell on Hiroshima and Nagasaki.
Japan surrendered on August 15th.
Operation Olympic was canled.
Project Thunder was terminated on August 20th, 1945.
Total production 1007400 rounds.
The actual mechanism of the M2 he rounds enhanced effectiveness involved complex terminal ballistics.
When the 150 grain projectile struck a target at 2,700 ft pers, it carried 2,427 ft-lb of kinetic energy.
The impact deceleration occurred over approximately 8 in of tissue penetration.
Basic physics meant this deceleration triggered the internal RDX charge.
The eight grains of RDX inside the projectile detonated with a velocity of 27,000 ft per second.
This is called detonation velocity, different from deflration, an explosion rather than burning.
The energy release was approximately 35 jewels, enough to fragment the projectiles copper jacket into 1520 pieces weighing 312 grains each.
These fragments radiated outward in a roughly spherical pattern, creating a temporary wound cavity, 4.2 times larger than standard M2 ball ammunition.
In ballistic gelatin tests, standard rounds created permanent wound cavities measuring 1.2 in in diameter.
M2 H rounds created cavities measuring 5.1 in in diameter.
The difference in a human body meant significantly increased hydrostatic shock and tissue damage.
Against vegetation, the effect was even more pronounced.
Jungle combat often meant shooting through banana leaves, vines, bamboo, and light brush.
Standard ammunition would lose velocity and potentially tumble after passing through multiple layers.
The M2 he round would detonate upon hitting heavy vegetation, clearing a small area and potentially injuring personnel behind cover.
Field testing showed a single M2H round could clear approximately 2.3 square ft of light vegetation, leaves, and vines.
Against bamboo, the round would shatter stalks within a 6-in radius.
This made the ammunition particularly effective for breaking up ambushes and engaging targets using natural cover.
But the limitations were significant.
First, the rounds were temperature sensitive.
Below 32°, the RDX could become unstable during firing, causing incomplete detonation.
Above 110°, the explosive could degrade or potentially detonate from shock.
without firing.
The Pacific theat’s temperature range was generally suitable, but weapons left in direct sunlight could exceed safe limits.
Second, the increased chamber pressure accelerated parts wear beyond just the barrel.
The bar’s bolt face showed accelerated erosion.
The extractor, the small claw that pulled spent cases from the chamber, wore 40% faster.
The operating rod that connected the gas piston to the bolt showed stress cracks after approximately 5,000 rounds mixed standard and M2H.
Third, the ammunition was less accurate.
The explosive primers slightly erratic detonation introduced minor velocity variations.
At ranges under 200 yd, this was negligible.
At 400 yardds, group sizes increased from 4 in to 7 in.
The bar wasn’t designed for precision fire anyway, but the degradation was measurable.
Fourth, the sound signature was distinctive.
Standard 30 or six gunfire produced a sharp crack.
M2 H rounds produced a crack followed a fraction of a second later by a pop from the detonation.
Experienced Japanese soldiers learned to recognize this signature.
It became a targeting indicator.
If you heard the double sound, that position had a thunder rifle.
Marines adapted to these limitations.
They learned to store magazines in shade and check ammunition temperature before missions.
They learned to clean weapons more frequently and request parts replacements earlier than with standard ammunition.
They learned to mix standard and M2H magazines rather than using exclusively modified ammunition, preserving the special rounds for critical moments.
Some Marines didn’t like the M2 he rounds.
The increased recoil was unpleasant.
The accelerated wear meant more maintenance.
The occasional feed failure could be fatal in combat.
Private First Class David Wong, Baker Company, told his sergeant he preferred standard ammunition because it was more reliable.
Others swore by them.
Corporal Mitchell, after using M2 he rounds in 23 engagements between November 1944 and March 1945, requested nothing else.
His reasoning was simple.
They keep the Japs heads down longer.
That’s worth cleaning my weapon twice as often.
The enemy perspective came primarily from interrogation reports.
Lieutenant Teeshi Yamamoto, captured on Bugganville in January 1945, described his unit’s experience.
We could not understand what weapon made such wounds.
Men would fall and explode.
We thought perhaps grenades, but there was no throw.
The Americans fired their rifles and our men exploded.
It affected morale severely.
Japanese medical personnel examining their own casualties noted the unusual fragmentation patterns and explosive residue.
Several intelligence reports referenced American explosive bullets, but the Japanese never determined the rounds were standard ammunition with modified primers.
They assumed it was an entirely new weapon system.
This confusion was strategic gold.
The Japanese couldn’t effectively counter a weapon they didn’t understand.
On September 2nd, 1945, Japan formally surrendered aboard USS Missouri.
Within weeks, the US military began rapid demobilization.
Experimental weapons programs were evaluated for peaceime relevance.
Project Thunder didn’t make the cut.
On October 15th, 1945, the War Department ordered all remaining M2H ammunition recalled to Aberdine, proving ground for disposal.
Approximately 89th al 200 rounds remained in inventory.
These were destroyed by controlled detonation between October and December 1945.
The manufacturing equipment at Aberdine was dismantled.
The technical specifications were classified secret and archived.
The ammunition’s combat use was similarly classified.
Marines who’d used the rounds were ordered not to discuss them.
Afteraction reports mentioning M2H ammunition were redacted or reclassified.
The program disappeared from official history.
Several factors drove this decision.
First, the HEG convention concerns, while legally unfounded, presented a public relations problem.
The US military had prosecuted German soldiers for using prohibited ammunition, having used questionable ammunition themselves, even if technically legal, was awkward.
Second, the ammunition’s limitations made it impractical for peaceime production.
The cost per round was 340% higher than standard ammunition.
The shelf life was 18 months versus 30 years for standard rounds.
The storage requirements were demanding for a peaceime military focused on cost efficiency.
M2 he made no sense.
Third, atomic weapons rendered conventional infantry ammunition improvements relatively insignificant.
The military’s focus shifted to nuclear weapons, guided missiles, and jet aircraft.
Small arms development received reduced priority and funding.
The classification remained until 1980.
The National Archives, processing World War II documents for declassification, discovered Project Thunder files.
A review board determined the technical information was no longer sensitive.
The Soviet Union had developed similar ammunition decades earlier.
On March 12th, 1980, Project Thunder was declassified.
By then, most participants were dead or elderly.
Jimmy Mitchell had left the Marines in 1946, worked as a machinist in Worcester, Massachusetts, and died in 1977.
He never told his family about the red banded ammunition.
His service records mentioned only that he’d served in the Pacific theater.
The technology itself evolved.
Modern explosive ammunition exists in various forms.
The Ralphos MK21150 caliber round developed in Norway in the 1980s uses similar principles.
a conventional projectile with an explosive component for enhanced effect.
The US military adopted it for use against material targets and light armor.
High explosive incendiary ammunition for aircraft cannons uses the same basic concept at larger scales.
The 20 mm rounds fired by the M61 Vulcan cannon contain explosive charges that detonate on impact.
The principle Captain Walsh explored in 1944 became standard for air-to-air combat.
But no modern equivalent exists for infantry rifles.
The technical challenges, pressure management, reliability, cost remain prohibitive.
The M2 round was a wartime expedient, brilliant in its simplicity, but impractical for widespread use.
Its legacy exists primarily in what it demonstrated that battlefield innovation could emerge from creative application of existing components.
Walsh didn’t invent new explosives or new weapons.
He combined existing elements, Browning’s rifle, Springfield’s cartridge, the M2 primer in a novel way that multiplied effectiveness.
This approach would resurface repeatedly in military development.
The Navy’s Failank CIWS combined existing radar technology with an existing cannon.
The Air Force’s JDM program converted unguided bombs into precision weapons by adding GPS guidance.
Innovation through integration rather than invention.
The M2H round also demonstrated the importance of testing weapons in actual combat conditions.
Laboratory testing at Aberdine showed promise.
Combat on Buganville proved effectiveness.
Environmental challenges on Ewima revealed limitations.
No amount of theoretical testing could replace operational experience.
Jimmy Mitchell rotated back to the United States in April 1945.
He’d fired approximately 2,400 rounds of M2H ammunition in combat, roughly 12% of the total ever used.
His bar required three barrel replacements and numerous parts changes.
He never lost a firefight.
He received no special decoration for his use of experimental ammunition.
That would have required acknowledging the program existed.
He got a Purple Heart for a minor shrapnel wound on Bugganville and a Bronze Star for General Valor.
Standard medals for standard service.
After the war, he occasionally wondered about those red banded rounds, why they’d been issued, where they’d gone, whether other Marines had used them.
He asked a few fellow veterans, but found no one who’d heard of them.
Eventually, he stopped asking.
The war receded into memory, classified or not.
Captain Theodore Walsh, the Ordinance Corps officer who developed the concept, remained at Aberdine Proving Ground until his retirement in 1962.
His personnel file makes no mention of Project Thunder.
After declassification in 1980, a military historian interviewed him.
He was 87 years old and remembered the project clearly.
“We knew it would work,” he said.
“The question was whether it would work well enough to justify the complications in combat.” Apparently, it did, but war ended before we could refine it properly.
He died in 1984.
Sergeant William Davis, Mitchell’s squad leader on Bugenville, made the Marines a career.
He retired as a master gunnery sergeant in 1965, having served in Korea and two tours in Vietnam.
He trained thousands of Marines in infantry tactics.
None of them heard about M2 ammunition because he followed orders and kept it classified.
In 1982, after the declassification, a researcher contacted him.
He was 64 years old, living in North Carolina.
He confirmed the ammunition’s effectiveness, but emphasized the weapon wear issues.
Good for emergencies, he said, not good for daily use.
But when the Japs came up that hill, I was damn glad we had them.
He died in 1998.
The Japanese soldiers who encountered the Thunder Rifles left scattered records.
Few survived the war.
Those who did rarely discussed their combat experiences.
Postwar Japan focused on rebuilding, not remembering.
One account exists from Sergeant Kenji Takahashi, captured on Bugganville in February 1945, who returned to Japan after the war.
In a 1987 interview for a local history project in Yokohama, he mentioned strange American bullets that exploded.
He didn’t elaborate.
The interviewer didn’t follow up.
The reference exists in an archive untransated until 2003.
The ammunition itself is gone.
All 187400 rounds either fired in combat or destroyed after the war.
No examples exist in museums or private collections.
A few empty cartridge cases might remain in soil on Buganville or Pleu, slowly corroding in tropical conditions.
What remains is data, reports, statistics, the dry record of weapons tested and battles fought.
And beneath that data, lives.
Men who carried experimental ammunition into combat, not knowing if it would save them or explode in their faces.
Men who pulled triggers and watched enemies torn apart by their own innovation.
Men who survived and stayed silent for 35 years because classified meant classified.
They were 19, 20, 23 years old.
Kids from Massachusetts and North Carolina and California.
They were handed yellow taped magazines and told, “Use these.” They did.
They survived battles that should have killed them.
They came home and never told anyone because orders were orders.
This is their story.
Finally declassified.
Finally told.
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Where are you watching from? Did any of your family serve in the Pacific? What other classified World War II weapons do you want to hear about? to Jimmy Mitchell, Theodore Walsh, William Davis, and the 20ome 400 Marines who carried red banded ammunition into combat.
Your silence kept secrets, but your service kept freedom.
We remember.
Finally, we
