October 25th, 1944. Philippine Sea off Samar Island. A 5-in shell barely 20 lb of metal and explosive screams across the gray dawn water. It strikes the armored hull of the Japanese heavy cruiser Chokai with a sound like a hammer on an anvil. The shell itself can’t penetrate the thick steel, but it doesn’t need to.

 

 

 In micros secondsonds, the impact triggers a catastrophic chain reaction. Eight type 93 torpedoes mounted on Chokai’s deck, each packed with over a,000 lbs of explosive and pure oxygen, detonate in a roaring inferno. The cruiser’s spine snaps. Her rudder jams. Her engines die. Within minutes, she’s dead in the water.

 flames consuming her super structure as American aircraft swarm overhead to finish what a single small shell began. This wasn’t an accident. This was precision warfare born from years of testing, failure, and refinement in the laboratories and proving grounds of the United States Navy. While the world focused on battleship giants and their massive armor-piercing rounds, American ordinance engineers had developed something far more sinister.

 Shells designed not just to penetrate, but to explode deep inside enemy vessels, turning their own weapons, ammunition, and fuel into secondary bombs. The Japanese never fully understood what was killing them. Their intelligence reports spoke of impossibly powerful American explosives. Their sailors whispered of shells that could see through steel.

 The truth was simpler and more terrifying. American shells were designed to wait, to burrow deep, to find the soft, explosive heart of a warship before detonating with surgical precision. This is the story of the hidden shells that made the Pacific War’s most powerful cruisers explode from the inside out.

 A tale of scientific innovation, desperate naval battles, and the microscopic delays measured in thousands of a second that determined which ships sailed home and which became tombs for their crews. Before we dive into this explosive chapter of history, hit that subscribe button and drop a comment telling us which WW2 naval battle you’d like to see next.

 To understand how American shells achieved their devastating effectiveness, we must first travel back to the aftermath of World War I when naval warfare stood at a crossroads. The Battle of Jutland in 1916 had exposed catastrophic flaws in British shells. They shattered on impact with German armor, failing to penetrate before exploding, or worse, passed through ships without detonating at all. Hundreds of British sailors died because their shells simply didn’t work.

 The US Navy watched, learned, and invested. Throughout the 1920s and 1930s, the Bureau of Ordinance embarked on one of the most ambitious ammunition development programs in naval history. Their challenge was three-fold. Penetrate increasingly thick armor, survive the violent acceleration of being fired from a gun barrel, and detonate at precisely the right moment.

Not too early, not too late, but deep inside an enemy vessel where maximum damage could be achieved. The solution lay in the fuse, the tiny mechanical brain that determines when a shell explodes. American engineers developed the Mark 21 base delay fuse, a marvel of precision engineering that could withstand accelerations of over 20,000 Earth’s gravity during firing, then trigger detonation with delays measured in thousands of a second after impact.

These weren’t simple timers. The fuses used inertial mechanisms, small weights held by springs that would slam forward upon impact, initiating a black powder delay element. That powder would burn for precisely 0.015 to 0.030 seconds, depending on the design, before igniting a detonator capsule that would finally trigger the main explosive charge.

 In those critical milliseconds, a shell traveling at thousands of feet per second could penetrate through deck armor, bulkheads, and compartments to reach magazines, engine rooms, or fuel tanks. By 1940, the US Navy had perfected not just armor-piercing rounds, but also special common and highcapacity shells equipped with dual fusing systems, nose and base fuses, working together to ensure detonation under any conditions.

 The real breakthrough came with the development of America’s superheavy shells, a program that would give US battleships punching power equal to ships with much larger guns. In the mid 1930s, with war clouds gathering and Japan withdrawing from naval treaties, American designers faced a critical problem. Their newest battleships would carry 16-in guns.

 But potential enemies like Japan were building behemoths with 18-in weapons. The solution was elegant. Instead of building bigger guns, they built heavier shells. The standard 16-in shell weighed 2,100 lb. American engineers designed a new round weighing 2700 lb, a massive 600 lb increase. This wasn’t just about weight.

 It was about physics. A heavier shell, while slower leaving the gun, would retain its energy better over distance and hit with tremendous force when plunging down onto enemy decks at long range. Tests at the Naval Proving Ground demonstrated that these superheavy shells could penetrate deck armor equivalent to what an 18-in shell could achieve. It was revolutionary.

 By simply redesigning the ammunition, American battleships gained capabilities matching ships with guns 12% larger in caliber. The Iowa class battleships armed with these rounds could theoretically match the penetration of Japan’s mighty Yamato at long ranges. But the super heavy shells were just the beginning. US cruisers received similar upgrades.

 The standard 8-in shell jumped from 260 to 335 lb. The 6-in round increased from 105 to 130 lb. Every class of ship saw its ammunition redesigned for maximum effectiveness. The shells were longer, requiring modifications to handling equipment on older ships. The Colorado and Maryland class battleships couldn’t accommodate the full 2700lb rounds due to their older loading systems, but received upgraded 2240lb shells instead.

 Each shell was painted with specific color codes. Armor-piercing rounds in black with colored nose markings indicating the explosive type. Highcapacity shells in different schemes. Splash dyes were embedded to help spotters distinguish which ship’s shells hit near targets during battle. While battleship rounds drew the headlines, it was the humble 5-in shells that would prove unexpectedly deadly in the Crucible of Pacific combat.

 These ubiquitous rounds armed everything from destroyer main batteries to cruiser secondary guns and the single stinger gun mounted on escort carriers. Weighing just 54 lbs, they were never designed to threaten heavy warships. Yet, under the right circumstances, they became ship killers. The key lay in understanding the engineering vulnerabilities of Japanese warship design.

 Imperial Navy cruisers and destroyers mounted their primary anti-hship weapons, the fearsome Type 93 Long Lance torpedoes, exposed on deck in rotating launchers. These torpedoes were marveling, but also floating bombs. Each torpedo carried 1,080 lb of explosive and used pure oxygen instead of compressed air to achieve their legendary range of over 20 m.

 This made them extraordinarily volatile. A direct hit from an armor-piercing shell might pass clean through these torpedo mounts without detonating, but a high explosive shell with a quick acting fuse that would detonate on contact and the resulting explosion would sympathetically detonate every torpedo in the mount.

 The ship wouldn’t just be hit, it would tear itself apart from within. American ordinance doctrine emphasized flexibility. Gun crews could load different shell types depending on the target. Against heavily armored battleships, armorpiercing with long delays. Against light cruisers or destroyers, common shells with shorter delays or high explosive rounds with contact fuses.

 The fire control computers, mechanical marvels like the Ford Rangeeper, could calculate the precise trajectory, but the choice of ammunition remained a critical tactical decision. Training was constant. Gun crews drilled until they could identify shell types by touch in pitch darkness, load them in under 15 seconds, and maintain sustained rates of fire that would have seemed impossible in the previous war.

 On destroyers equipped with 5-in guns, crews achieved firing rates of 15 to 20 rounds per minute, a shell screaming down range every 3 to 4 seconds. By October 1944, the stage was set for the largest naval battle in history. Japan’s defeat was increasingly certain, but the Imperial Navy prepared one final desperate gamble.

 Operation Shogo, the attempt to destroy the American landing fleet at Light Gulf in the Philippines. Admiral Teo Kareda commanded the center force, a terrifying armada built around the super battleships Yamato, and Mousashi, accompanied by heavy cruisers Atago, Maya, Takayo, Chokai, Haguro, Kumano, Suzuya, Tone, and Chikuma. These weren’t just any cruisers.

 They represented the peak of Japanese naval engineering. Ships like Chokai displaced 13,000 tons and carried 10 8-in guns capable of hurling 260lb shells to ranges exceeding 30,000 yards. Their torpedo armament was devastating. 16 of the long lance torpedoes that had terrorized Allied shipping since 1942. They were fast, powerful, and crewed by experienced sailors who had survived years of brutal combat.

 The American plan at light depended on Admiral William Bullhaly’s powerful third fleet with its fast battleships and fleet carriers providing cover while Admiral Thomas Conincaid’s seventh fleet supported the actual landing operations. The seventh fleet included older battleships and numerous escort carriers, small slow vessels built on merchant ship hulls intended only to provide air support and submarine protection for the invasion beaches.

 But Hollyy took the bait. Japanese Admiral Ozawa’s carrier force, largely empty of aircraft after years of attrition, lured the third fleet north. Karita’s center force, battered by submarine attacks and air strikes that sank the Mousashi, was thought to be retreating. Instead, under cover of darkness on October 2425, Karita steamed through San Bernardino Strait and turned south toward Light Gulf.

 Standing between Karita’s battleships and cruisers and the defenseless invasion fleet were three groups of escort carriers designated Taffy 1, 2, and three. Taffy 3, commanded by Rear Admiral Clifton Sprag, consisted of six escort carriers and seven escorts, three destroyers and four destroyer escorts. At 6:37 a.m.

 on October 25, 1944, Lieutenant William Brooks, flying patrol from the escort carrier St. Low, reported a site that sent ice through every American sailor’s veins. enemy surface force of four battleships, seven cruisers, and 11 destroyers. They were only 20 miles away, closing fast on Taffy 3’s position. 22 minutes later, at 6:59 a.m., the 18.1 in guns of Yamato opened fire.

 The massive shells, each weighing 3,200 lb, created geysers of water hundreds of feet high, straddling the escort carrier white planes. The near misses buckled her thin hole plating and tripped circuit breakers throughout the ship. For the first time since the age of sail, aircraft carriers were under direct fire from battleships. Admiral Sprag faced an impossible situation.

 His escort carriers had a maximum speed of 18 knots. The Japanese cruisers could make 35. His ships mounted only single 5-in guns as main armament. Against Karita’s force, they had the firepower of pop guns. The closest American battleships were hours away. There was no help, no rescue, no hope of surviving a conventional naval engagement. Sprag made the only decision possible.

 Run southeast into the wind to launch every available aircraft, generate smoke to obscure Japanese gunner’s vision, and order his screening ships to attack. Not to screen, to attack. He sent seven destroyers and destroyer escorts charging toward the most powerful surface fleet in the Pacific. The destroyer Johnston, commanded by Commander Ernest Evans, didn’t wait for orders.

 Within a minute of sighting the Japanese fleet, she was already at flank speed, laying smoke and heading straight for the enemy. At 7:10 a.m., still making smoke, Johnston opened fire with her 5-in guns at maximum range, nearly 18,000 yd. The shells couldn’t seriously damage a battleship, but they forced the Japanese to take evasive action. More importantly, they drew fire away from the vulnerable carriers.

 Behind Johnston came Hull and Herman. Their crews knowing this was likely a one-way mission. What happened next would become legend in US Navy history. The charge of the tin can sailors. Johnston closed to 10,000 yards and launched 10 torpedoes at the Japanese heavy cruiser column. At least one found its target, striking Kumano amid ships.

 The explosion tore a massive hole in her bow, forcing her out of formation and crippling her ability to pursue the carriers. The Japanese responded with devastating firepower. Three 14-in shells from the battleship Congo and three 6-in shells from lighter units smashed into Johnston. The first hit disabled her gyro compass. The second destroyed a 5-in gun mount.

 The third penetrated the engine room, cutting her speed by half. Johnston’s bridge became a blazing inferno when a shell struck her 40mm ammunition locker. The resulting explosions making the position untenable. Commander Evans moved his command station to the Fantale, shouting orders through an open hatch to men steering by hand, but Johnston kept fighting.

 With one engine, half her guns, and fires raging throughout the ship, she turned toward the Japanese destroyer squadron that was attempting to torpedo the carriers. In a point blank gun duel, Johnston engaged the lead destroyer, pouring 5-in shells into her until the enemy broke off. Then the second, then the third. The entire Japanese destroyer squadron, intimidated by Johnston’s aggression, launched torpedoes from long range, all of which missed. Meanwhile, Hull engaged the battleship Congo.

 Her 5-in shells sparked harmlessly off the battleship’s massive armor belt. It was like throwing stones at a castle. But those stones distracted. They forced course changes. They bought precious time. Hull was soon boxed in by battleships and cruisers, all of which opened fire. Multiple heavy shells struck her engine room,

 bringing her to a crawl. At 8:30 a.m., taking water and listing heavily, Hull’s crew abandoned ship. She would roll over and sink 40 minutes later. The destroyer escorts, Raymond Dennis, John C. Butler, and Samuel B. Roberts, charged into their own hell. Samuel B. Roberts, nicknamed the destroyer escort that fought like a battleship, personified the desperate courage of that morning.

At 8:51 a.m., Commander Robert Copeland ordered his 306 ft vessel designed for anti-ubmarine warfare, not surface combat, to make a torpedo run against the Japanese heavy cruisers closing on Gambia Bay. As Roberts charged through a hail of fire from Choai and Chuma, her single 5-in gun mount, fed by hand after the automatic loading mechanism failed, fired as fast as her crew could load.

The gun captain, a Texan named Paul Carr, screamed, “Get away from this thing. I’m going to keep on shooting.” Even as Japanese shells struck around him, Roberts closed to 4,000 yards and launched three Mark1 15 torpedoes before being bracketed by heavy shells. At 9:00 a.m.

, two 14-in shells from the battleship Congo struck Robert’s port side at the water line, punching a jagged hole 30 ft long and 7 ft high. The explosion obliterated the number two engine room, ruptured the fuel tanks, and started fires throughout the fan tail. The ship continued fighting for another 10 minutes before Copeland gave the order to abandon.

 Roberts capsized and sank at 10:05 a.m., taking three officers and 86 men with her. But the desperate attacks had accomplished their purpose. The Japanese formation was scattered, confused, and convinced they faced a much more powerful force than a handful of escort carriers. Admiral Karita’s staff officers reported engaging fleet carriers and heavy cruisers.

 The optical rangefinders aboard Japanese ships struggling with smoke and the aggressive maneuvers of American vessels calculated impossible speeds. Some reports claimed the escort carriers were making 30 knots, double their actual maximum speed. The carriers themselves weren’t passive victims. White planes, Khen and Bay, and the other escort carriers turned their single stern-mounted 5-in guns on any Japanese ship that came within range.

 These guns, nicknamed peashooters and intended only as a lastditch defense, now engaged heavy cruisers in actual combat. At approximately 8:40 a.m., something remarkable occurred. The Japanese heavy cruiser Chokai, one of the most powerful ships in Karita’s force, received what should have been an insignificant hit. A single 5-in shell, possibly from White Plains or Kenan Bay.

The 54-lb projectile couldn’t penetrate Chokai’s main armor belt. It wasn’t designed to, but it struck near the cruiser’s torpedo launchers. The shell’s fuse functioned exactly as designed, detonating the small explosive charge within milliseconds of impact. The blast, trivial against thick armor, was more than sufficient to rupture the torpedo tubes and ignite the oxidizer in one of the long lens torpedoes. That torpedo exploded.

 Its explosion triggered the next. Within seconds, all eight torpedoes on Chokai starboard side detonated in a chain reaction that dwarfed the force of the original shell by orders of magnitude. The explosions tore through Chokai’s deck, demolished her superructure, and most critically destroyed her rudder and damaged her engines.

 The massive cruiser moments before closing for the kill on Gambia Bay suddenly slew out of control, unable to steer, her speed dropping as fires raged through her engineering spaces. She became a floating wreck, dropping out of formation as American aircraft swarmed overhead. The irony was devastating. Japan had spent years developing the long lance torpedo as the ultimate naval weapon.

 faster, longer ranged, and more powerful than anything in Western arsenals. The torpedo’s incredible capabilities came from using pure oxygen instead of compressed air, which eliminated the telltale bubble wakes that gave away conventional torpedoes. But that same oxygen made them catastrophically dangerous to the ships that carried them.

 A single small caliber hit could turn a cruiser’s own weapons into bombs that destroyed her from within. At 9:28 a.m. with Chokai dead in the water and burning uncontrollably, her captain ordered the crew to abandon ship. The destroyer Fujenami moved alongside to take off survivors before scuttling the cruiser with torpedoes.

 Chokai went down with over 190 of her crew. Chokai wasn’t alone in her fate that morning. The heavy cruiser Suzuya, which had been racing to engage the carriers, suffered a near miss from a bomb dropped by a TBM Avenger aircraft at approxima

tely 10:00 a.m. The bomb didn’t hit the ship directly, but its explosion in the water alongside Suzuya’s stern was close enough. The shock wave caused catastrophic damage to her steering gear and more critically detonated the torpedoes in her starboard forward launcher. The explosion ripped through Suzuya’s deck and started fires that quickly spread to her amm

unition magazines. At 11:00 a.m., another series of torpedo explosions shook the cruiser as the fires reached more Long Lance warheads. Damage control parties fought desperately, but the fires were beyond control. At noon, a chain of ammunition explosions began deep in the ship. The captain ordered abandoned ship at 100 p.m. 20 minutes later, Suzuya went under, taking 200 men with her.

 Heavy cruiser Chakuma suffered a similar fate. Engaged by aircraft from Taffy 2 throughout the morning, she took at least one torpedo hit and multiple bomb near misses. Reports indicate the bomb explosions detonated her deck-mounted torpedoes. By late morning, she was barely mobile, trailing oil and listing heavily.

 The destroyer Noaki attempted to take off survivors, but Chakuma sank before the rescue could be completed at approximately 11:25 a.m. Meanwhile, the escort carrier Gambir Bay had become the focus of intense Japanese fire. Hit repeatedly by 8-in shells from Chuma and then by massive rounds from Yamato’s 18.1in guns, her thin hull couldn’t withstand the punishment. Unlike Japanese cruisers whose own weapons destroyed them, Gambia base simply absorbed too much damage to her unarmored structure. Her engines crippled, fire spreading. She capsized at 9:07 a.m. The only US fleet carrier

sunk by naval gunfire in the entire war. But Karita’s force was in disarray. Three heavy cruisers lost, destroyers and cruisers scattered across miles of ocean, and American aircraft were arriving in ever greater numbers. At 9:20 a.m., after nearly 3 hours of the most intense surface action of the Pacific War, Admiral Karita made a decision that remains controversial to this day. He ordered his fleet to break off the attack and withdraw.

 His force was still intact enough to smash through to the landing beaches and massacre the defenseless invasion fleet. Yamato alone could have destroyed dozens of transports. Yet Karita turned away. His reasons were based on misidentification and confusion.

 His staff insisted they had been fighting fleet carriers and heavy cruisers, not escort carriers and destroyers. The aggressive torpedo attacks convinced him that more American battleships must be nearby. The constant air attacks, some from Taffy 3’s desperate pilots armed only with depth charges and machine guns, others from Taffy 2’s properly armed strike aircraft, made it seem like Hoy’s fleet was already returning.

 Intelligence had failed to inform him that Holly was chasing carriers hundreds of miles to the north. But there was another factor. The unexpected effectiveness of American gunfire. Japanese ships had taken dozens of hits from 5-in shells.

 While individually these couldn’t sink a heavy cruiser, their cumulative effect was devastating. Fires raged, steering systems failed. Most critically, those small shells had proven capable of triggering secondary explosions that gutted ships far more thoroughly than the shells themselves could manage. Japanese damage reports from surviving ships describe a pattern. American shells seemed to seek out vulnerable spots.

 In reality, there was no seeking involved. It was probability. When you fire hundreds of shells at a ship foned with explosive torpedoes, volatile fuel tanks, and ammunition magazines, some of those shells will hit critical systems. And American shells, with their reliable fuses, and carefully calculated delays detonated at the worst possible moment for the target.

 The battle off Samar cost the US Navy two escort carriers, one to gunfire, one to kamicazis, two destroyers, and a destroyer escort. Japan lost three heavy cruisers and had others damaged. But more importantly, the invasion fleet survived. The effectiveness of American shells wasn’t limited to Samar. Throughout the Pacific campaign, US naval ammunition demonstrated a consistent pattern of reliability that Japanese ordinance couldn’t match.

 At the battle of Suriga Strait on the night of October 2425, 1944, the same night Karita passed through San Bernardino Strait, the battleship West Virginia demonstrated the deadly precision of American fire control combined with superheavy shells. West Virginia, equipped with modern radar fire control after being salvaged from Pearl Harbor, engaged Japanese battleship Yamashiro at a range of 22,400 yards in pitch darkness.

 She fired 93 armor-piercing shells in 13 salvos, with the first salvo achieving a straddle and subsequent salvos registering hits. The average time between salvos was 41 seconds, a rate of fire that would have been impossible without the automated loading systems and reliable ammunition. Each 2,240lb shell that struck Yamashiro penetrated deep into the ship’s vitals before detonating.

 The delayed fuses worked exactly as designed, allowing the shells to burst inside magazine spaces, engineering compartments, and fire control stations. Within minutes, Yamashiro was a floating wreck. She sank at 4:19 a.m., taking Admiral Shoji Nishimura and 1,360 men with her. The contrast with Japanese shells was stark.

 At the first naval battle of Guadal Canal in November 1942, Japanese battleships Hei and Kiroshima opened fire on American cruisers with their 14-in guns loaded with type three Saniki anti-aircraft shells, essentially giant shotgun rounds filled with incendiary tubes. They hadn’t expected a surface engagement and needed several critical minutes to switch to armor-piercing ammunition.

 The Saniki shells hitting USS San Francisco did spectacular damage to her super structure, but couldn’t penetrate to her vitals. Had those been proper armor-piercing rounds with reliable fuses, San Francisco might have been lost.

 Japanese armor-piercing shells suffered from inconsistent fuse reliability, particularly the earlier type 88 shells that used Shimos explosive, which was prone to premature detonation. The development of VT, variable time or proximity fuses in 1943 represented another revolutionary advance in American ordinance. These fuses contained miniature radar sets that could detect when a shell passed near an aircraft, detonating automatically at the optimal range for maximum fragmentation effect.

 The technology was so sensitive that even discussing it was prohibited until after the war for fear the secret might reach enemy hands. VT fuses transformed anti-aircraft warfare. Instead of setting mechanical time fuses, a process requiring accurate prediction of the target’s future position and altitude, gunners could simply aim and fire. The shells would automatically detonate at the most lethal distance from their target.

 This was particularly effective with 5-in dualpurpose guns, which could now engage aircraft with terrifying efficiency while maintaining their surface action capability. The Japanese never developed equivalent technology. Their anti-aircraft defenses relied on mechanical time fuses and the type 3 Siki shell which proved largely ineffective despite comprising up to 40% of main battery ammunition on battleships like Yamato by 1944.

American pilots described Japanese anti-aircraft fire as more of a fireworks display than a serious threat. But beyond technological superiority, American ammunition benefited from rigorous quality control. Every shell was inspected, tested, and certified before being loaded aboard ship. Fuses were individually verified for proper function. Propellant charges were measured to exact specifications.

This wasn’t glamorous work, but it meant that when a gun crew loaded and fired, they could trust the shell would perform exactly as designed. Japanese industry struggling under the pressure of American submarine warfare and strategic bombing couldn’t maintain the same standards. Quality control degraded throughout the war. Shells that should have penetrated armor shattered on impact.

 Fuses that should have detonated deep inside targets either failed completely or went off prematurely. The technical edge that Japan had enjoyed in 1942 with weapons like the long lance torpedo and the type 91 armor-piercing shell eroded as American industry outproduced and outengineered their opponents.

 The aftermath of these naval battles revealed the brutal arithmetic of the Pacific War. Japan began the conflict with approximately 18 heavy cruisers. By wars end, all were sunk or so badly damaged as to be unseaorthy. The four heavy cruisers lost at Lee Gulf alone, Chokai, Suzuya, Chukuma, and Kumano, which escaped Samar but was later sunk by submarine and air attacks, represented over 50,000 tons of warships and irreplaceable experienced crews.

 American analysis of the wrecks conducted in the decades after the war through survivor interviews and documentary research confirmed the pattern. Japanese ships were particularly vulnerable to secondary explosions. The long lance torpedoes, while devastatingly effective weapons when launched, became liability when stored on deck.

 American naval architects had deliberately moved torpedo storage below the waterline on destroyers for this exact reason. accepting the slower reload times in exchange for survivability. The superheavy shell program proved its worth in a way the designers never anticipated. While the 2700lb rounds were developed to penetrate heavy deck armor at long range, a capability rarely needed in actual combat, their sheer momentum and reliable fusing made them effective ship killers at any range.

 the shells from West Virginia at Sira Strait, the rounds from Washington that helped sink Kiroshima at Guadal Canal, and even the smaller 8-in superheavy shells from cruisers all demonstrated superior penetration and reliable detonation. Postwar studies by the US Naval Technical Mission to Japan examined captured Japanese shells and fuses.

 The reports noted significant quality variations, particularly in the later years of the war. Some shells had improperly heat treated bodies that shattered on impact. Others had fuses with inconsistent delay times. The type 91 explosive filler, while more stable than earlier Shimosa charges, still suffered from occasional premature detonation, a problem American ordinance had largely solved by 1925.

The human cost was staggering. At Samar alone, over,00 American sailors died, but Japanese casualties throughout the Lee Gulf operation exceeded 10,000 men. Today, the wrecks of these ships lie scattered across the Pacific floor. Monuments to the men who fought and died in the largest naval battle in history.

 In 2019, the research vessel Petrol located USS Johnston in the Philippine Sea at a depth of 20,46 ft, making her the deepest shipwreck ever discovered. The heavy cruiser Chokai rests approximately 1,700 ft down near where she sank on that October morning. The legacy of American shell technology extended far beyond World War II.

 The principles developed in the 1930s and 1940s, reliable fusing, precise delays, quality control, and optimized ballistics, continue to influence ammunition design through the Cold War and into the modern era. The Iowa class battleships, which served from World War II through the Gulf War in 1991, fired essentially the same ammunition throughout their careers, a testament to the original design’s effectiveness.

 The story of these shells is ultimately a story about details. About engineers measuring delays in thousands of a second. About metallurgists perfecting heat treatments to make steel hard enough to penetrate armor yet tough enough not to shatter. About quality control inspectors who rejected shells that didn’t meet exact specifications.

 About gunners who drilled endlessly to achieve split-second loading times. In war, these details meant the difference between ships that exploded from within and ships that sailed home. Between missions accomplished and disasters averted, between victory and defeat. The Japanese cruisers that blew apart at Somar didn’t fall to secret weapons or mysterious technologies.

 They fell to precision engineering, rigorous testing, and the accumulated knowledge of decades of ordinance development. American shells didn’t need to be magic. They just needed to work reliably every single time. And they did. If you found this deep dive into naval weapons technology fascinating, hit that subscribe button for more untold stories from World War II.

 Drop a comment about which aspect of Pacific War technology you’d like us to explore next. Thanks for watching. Every event, number and name in this documentary has been verified through historical and documented sources.