The HORRORS of the China Lake Grenade Launcher in Vietnam

On a Mekong Delta canal in 1968, a six-man SEAL squad holds position in the mangrove roots on the west bank and waits for a sampan to drift into the kill zone. The point man is carrying something that looks nothing like the standard M79 grenade launcher his army counterpart would have, a pump-action 40-mm weapon hand-built in a California desert lab specifically for this kind of fight.

When the sampan reaches 30 m, he cycles through four rounds in 4 seconds, each grenade arcing into the target before the first one has landed, the detonations walking across the kill zone while the squad’s rifles haven’t yet opened up. On the far bank, the sound implies a force several times the actual size of the element producing it.

One man, four explosions, the fire signature of a platoon. In the entire Vietnam War, that weapon was carried in combat by roughly 20 people. Only 22 were built, each one hand-fitted in a California tool room by an engineer who had produced a working prototype faster than his team could write the production drawings.

By the time the war ended, the bulk of them had been demilitarized and destroyed. Four are confirmed to survive, distributed between a Florida museum, a Washington archive, an Indiana test station, and a glass case in Ho Chi Minh City, where the People’s Army has kept one since the war.

The story of why 20 people needed a weapon nobody else had begins with what was broken about everything else. Kevin Dockery spent years inside Naval Special Warfare records as curator of the UDT/SEAL Museum, and his description of the M79 central flaw is exactly the kind of sentence that comes from reading enough after-action reports to know where the weapon failed.

Any SEAL who carried an M79 was very limited weapon during a close-in encounter of less than 15 m. The arming distance was 14 to 27 m. Inside that window, the round was a dead aluminum slug rather than a live bomb. But, the deeper tactical problem was the reload. Break the action open after one shot, and the grenad.i.er was holding an empty tube for 2 to 3 seconds while he reached for another round.

Six-man squad initiating an ambush on a canal 30 m wide. 2 seconds is time enough for the enemy to orient and respond. And a VC combatant who knew the sound of a single 40 mm launch and the pause that followed it understood what that pause meant about the number of attackers and the rate of incoming fire. The SEALs tried every solution the army offered.

The Colt XM 148 underbarrel attachment went through field evaluation in Vietnam in early 1967 and was rejected by the army by May of that year as unsatisfactory for operational use. Though the SEALs kept it because a single underbarrel shot was better than none. Springfield Armory’s T148E1 harmonica gun, a multi-shot repeating launcher with an open magazine, was evaluated by SEAL Team 1 and never reached combat.

Dockery’s assessment was that its open magazine would pick up dirt and debris like scoops as the weapon was moved through the jungle. And shot-to-shot muzzle velocity swung so wildly that accuracy was unrecoverable before the weapon even reached the line. What the SEALs needed was not a second shot under a rifle barrel.

They needed a weapon that could pour four 40 mm rounds into a kill zone in the opening seconds of an ambush before any surviving enemy could locate the source, assess the size of the force, or do anything useful in response. The army was developing its own solution on the army’s timeline. The SEALs went to their own navy.

The Special Operations Branch at Naval Ordnance Test Station, China Lake, California, had been built specifically to give the SEAL teams a quick reaction weapons shop that operated outside the standard procurement cycle. In 3 years of Vietnam War operations, that shop produced roughly 375 separate items for the teams.

Illumination flares, suppressed pistols, the Smith & Wesson Hush Puppy, day-night signal devices, electronic firing circuits, and dozens of other items for which no army contract existed and no army timeline applied. The I A Historic Aerospace Site Marker at China Lake notes that 75% of all air-launched weapons used in Vietnam were there.

The pump action grenade launcher was one item in a catalog of 375. The engineer assigned to it was Alfred F. Kermode. On September 1st, 1967, he filed US patent 3,435,549, which describes the weapon in the legally minimal language of a patent abstract as a pump type tubular magazine repeating firearm. More revealing than the abstract is the face page, where Kermode he listed his home address as 201 Cisco, Ridgecrest, California 93555, rather than the agency’s address.

Government employee inventions normally carry the institution’s location as the point of contact, not the inventor’s home. That home address on a Navy weapons patent says something specific about the speed and informality with which the special operations branch operated when it needed to move fast. Dockery records the development sprint in terms that would read like a misprint in any conventional procurement context.

It reportedly took longer to make a set of production drawings from the tool room prototype than it did to build the first weapon itself. Kermode had a functioning launcher before his engineers had documenting it. Each subsequent gun was hand fitted at China Lake, rather than assembled from interchangeable manufactured parts, which is why 22 ended up on Navy records rather than 200.

The highest serial number ever found was 50, on a stripped receiver discovered incomplete that may never have been built into a functioning weapon. And this is the actual source of the widely repeated claim that 50 were made. 50 is not the production figure. It is the ceiling of account that stopped before the project did. The weapon that came out of Kermode’s tool room had a squared-off aluminum receiver with a wooden stock and integral pistol grip, a 14-in barrel riding above a ribbed pump slide, and a rear sight that folded flat for movement

and flipped up into a ladder calibrated in 25-m increments from 75 to 400 m, nearly identical to the M79 sight, which meant a trained grenad.i.er could transition to the China Lake without relearning the range picture. The trigger guard was oversized to accept a gloved hand in the dark. Loading it worked the same way as feeding a pump shotgun, 3 40 mm rounds into the tubular magazine through a port in the bottom of the receiver.

A single pump to chamber the first round, and the spring held the remaining three in sequence. From that point, a trained operator could work through all four shots in roughly 4 seconds. At 200 m, the 40 mm rounds flight time is long enough that the final grenade can leave the muzzle before the first one reaches the target. Dockery put the practical result plainly, a skilled operator could fire four aimed shots before the first one landed.

The magazine had one hard limitation. It fed HE frag reliably and choked on nearly everything else. The fat-bod.i.ed buckshot rounds that SEALs favored for close work would not cycle cleanly through the tube, and the same problem affected some CS and flare rounds. A China Lake operator was a high-explosive fragmentation specialist, and inside the arming distance he had a sidearm like any other grenad.i.er.

The receiver also carried a larger than standard screw on the left side, a mount for a quadrant sight that would have allowed indirect fire use over obstacles. Though whether that capability was ever employed in combat is not in any record. The first China Lakes reached SEAL hands by mid-1968. On November 5 of that year, Vice Admiral Zumwalt launched Operation Sea Lords and committed five SEAL platoons to the Mekong Delta Riverine Campaign.

The brown water war was fought on canals narrow enough that both banks could be engaged simultaneously, through mangroves so dense that a squad’s actual size was invisible from the water until contact was already underway. The China Lake’s four-round heat profile was optimized for exactly this terrain. Close enough that the arming distance was rarely the limiting factor, with contact distances that made the opening volley speed more important than its range.

The primary record of its combat use is 12 words in a declassified document, SEAL Team One Command and Control Histories 1968, Enclosure Three, Special Topics, Performance of Weapons Systems, states that the 40 mm pump weapon has proven to be a good weapon and is being used by SEAL detachments in Vietnam. The language is present tense, meaning the weapon was in active use at the time of writing.

And no specific operation Canal Platoon or operator appears anywhere in the passage. A primary source photograph confirms one China Lake in a SEAL Platoon’s kit list, a SEAL Team two platoon of B in Thai, circa 1967-68, whose catalog long arm rack included 10 M60 A1s, four Stoner 63As, seven XM148 underbarrel launchers, one model 7188 assault shotgun, and one pump action grenade launcher.

16 men in the platoon, one China Lake in the rack, and no caption anywhere in the image identifies whose hands it went to. No SEAL operator who carried this weapon has ever been publicly named. Not in Dockery’s research, not in the Forgotten Weapons Technical Review from 2020, not in the UDT/SEAL Museum’s photo archive, which elsewhere names operators beside their weapons in dozens of wartime.

The men who brought it to the Mekong Delta left their endorsement in 12 words of a command history, and one of the 22 in a glass case in Vietnam. Neither document has a name attached to the man who fired it. Dockery’s own summary uses the word some with precision, “Very well received by some of the SEALs in the teams.

” 20 men carrying a weapon in a war where 100 SEALs were in country at any given time means the majority of SEALs never held one. The China Lake was loved by the handful who had it. The rest of the teams never knew it existed. The VC called the SEALs the men with green faces, a name derived from the camouflage paint, but distinguished night operators from conventional forces.

The UDT/SEAL Museum records that the VC put bounties on SEAL team members, and that in roughly six years of Vietnam operations a force that never exceeded 100 men in country accumulated 600 confirmed kills and some 300 more probable. A ratio so far outside what the enemy expected from a force that small that the SEALs occupied a particular space in the Viet Cong’s threat calculation before the China Lake ever arrived on a canal bank.

What the China Lake changed was the opening 4 seconds. A conventional M79 grenad.i.er’s fire signature in an ambush was a single hollow launch, the arc of one round, and the 2 to 3 second pause while he broke the action open and reloaded. From the receiving end, that signature was readable.

One grenad.i.er, one round at a time, with enough of a window between shots to begin counting the attackers. An enemy who understood the M79 could use the intervals between detonations to build a rough picture of the squad’s size. A China Lake grenad.i.er’s opening volley was 4 40-mm detonations in 4 seconds before the squad’s M16s had completed a single cycle.

The sound implied multiple grenad.i.ers operating in coordinated sequence, a fire volume inconsistent with what six men should be capable of producing. SEAL element that initiated with one China Lake arrived on a canal bank producing the acoustic signature of something several times its actual strength. And by the time any surviving member of the target could begin to reconcile that impression with the reality of the squad in the mangrove, the contact was effectively over.

In the Mekong Delta’s brown water war, where a six-man squad operated against a supply network that moved through canal crossings at predictable times, the first 4 seconds of a contact were often the only seconds that mattered. The China Lake was built to own those 4 seconds and give the squad everything it needed before the fight became a fight.

August 29th, 1969. The army standardized the M203 underbarrel launcher with a $2,953,000 sole-source contract to I for 10,000 units, confirmed in the December 1969 American Rifleman and the NRA contract record DAAG-25-70C-0127. The M203 attached beneath an M16 and gave a single sold.i.er a rifle and a grenade launcher in one weapon, which meant no dedicated grenad.i.er, no sidearm compromise, and no second man committed to a tube.

Against that offering, the China Lake’s hand-built production rate of perhaps six or eight weapons a year had no institutional response. Scaling to a thousand guns would have required tooling, drawings, and a contractor, and the Army had already given that contract to someone else 12 months after the first China Lakes reached SEAL hands.

Vietnamization narrowed the operational window from the other direction. The last SEAL Platoon departed Vietnam on December 7th. Special purpose procurement was the first budget category to contract when the political ceiling dropped on the war. Most of the 22 were demilitarized after the conflict ended.

Their receivers destroyed and their records archived in collections most researchers access. Four originals are confirmed to survive. Serial number two at the Naval History and Heritage Command in Washington, D.C. Serial number four at the National Navy UDT SEAL Museum in Fort Pierce, Florida. One unnumbered example at NSWC Crane in Indiana.

Serial number 13 at the War Remnants Museum in Ho Chi Minh City, which researcher Kent Saunders examined personally in 2010 and confirmed by reading the number stamped on the tang after museum authorities allowed him to partially disassemble it outside its display case. What the China Lake proved survived the hardware by decades. Kermode had demonstrated in a California tool room in 1967, with no production line and no manufacturer, that a repeating shoulder-fired 40-mm launcher was mechanically feasible, tactically transformative, and operationally suited

to the close-range ambush environment that special operations forces actually worked in. The Army, the Navy, and private contractors spent the following decades trying to build what he had already built at scale and with manufacturable parts. The Milkor MGL entered USMC service as the M32 in 2005, 38 years after Kermode filed his patent.

SACO adopted its own variant. Russia fielded the GM-94, a pump-action 43-mm launcher issued to Spetsnaz, drawing on the same proof of concept from the same era. One Naval Special Warfare retrospective assessed the moment with appropriate plainness. After four decades, the SEALs finally have their big grenade launcher.

US patent 3,435,549, filed September 1st, 1967. Inventor, Alfred F. Permode, 201 Cisco, Ridgecrest, California. 22 were built by hand. Fewer than 20 men carried one in combat. Four survived. The 12 words in the 1968 command history are declassified. The serial number on the weapon in Ho Chi Minh City is confirmed. The names of the men who fired it are not.