During a firefight near the Cambodian border on June 6, 1968, a 1st Infantry Division soldier got a pleasant surprise as he watched a North Vietnamese Army infantryman aim his rifle, pull the trigger and explode in a cloud of black smoke.

American troops later examined the remains of the NVA soldier and his exploded Chinese Type 56 rifle, removing some of its parts from the body. There was nothing was blocking the bore, the incident was attributed to poor metallurgy or bad ammo, but the situation was a little more complicated than it appeared.

While it is gratifying to see the direct results of your work, some times it is more effective to set the conditions for success and then stand back and let events unfold.  Project Eldest Son, a classified program of the Military Assistance Command Vietnam Studies and Observations Group (SOG), placed sabotaged ammunition in North Vietnamese Army ammo dumps. The success of Eldest Son exceeded all expectations.

Green Berets are trained to anticipate the second and third order effects of their actions. Eldest Son killed hundreds, but it frightened the entire North Vietnamese Army and sowed distrust between Vietnam and China at the highest levels of government.

The Studies and Observations Group was America’s top-secret special operations task force in the Vietnam War.  SOG’s operators worked directly for the Joint Chiefs, executing highly classified, deniable missions in Laos, Cambodia and North Vietnam. From 1966 to 1968, SOG was commanded by Colonel John K. Singlaub.

Singlaub was an old school unconventional pro.  Working for the OSS, he parachuted behind German lines in August 1944 to fight with the French Resistance fighters supporting the D-Day invasion during World War II.  After the war Singlaub joined the Central Intelligence Agency (CIA) and worked in Manchuria during the Chinese Civil War. In 1951 he became Deputy Chief of the CIA station in South Korea. Later he ran CIA operations in Manchuria during the Chinese Communist revolution and led troops in the Korean War, He was the perfect guy to run SOG.

SOG ran recon teams, normally consisting of two or three American Green Berets and four to six indigenous soldiers.  These teams ran deniable missions into Laos and Cambodia to gather intelligence, wiretap enemy communications, kidnap key enemy personnel, ambush convoys, raid supply dumps, plant mines and generally bring the joys of unconventional warfare to NVA rear areas.

While skulking around, these teams often encountered ammo caches with millions of rounds.  Being a Green Beret, Singlaub’s first inclination was to steal the ammo, but there was just too much of it and it was in very remote areas.  Demolition was not feasible as it would only scatter small-arms ammunition, not destroy it.

They could have booby-trapped the caches so that when the NVA picked up a case it would blow up, but that would have only impacted a small number of enemy soldiers and the NVA could develop countermeasures.  Singlaub came up with a deeper game.  He would booby trap the individual rounds of ammunition and give them back.

Like most unconventional tactics, ammunition sabotage was nothing new.  The best documented applications had been employed by the British during the Second Matabele War (1896-1897). In what is now Zimbabwe, British scouts (led by the American Frederick Russell Burnham) had slipped exploding rifle cartridges into enemy caches.

Similar techniques were used in the Waziristan campaign (1936–1939) against the Pathan tribesmen on India’s Northwest Frontier. Fighting insurgents who relied on captured ammunition made it simple to get sabotaged .303 rifle ammunition in enemy guns.

The plan was briefed all the way to the Joint Chiefs Joint Chiefs in the Pentagon. On August 30, 1967, they approved the plan and two weeks later, Singlaub watched a CIA technician load a sabotaged 7.62×39 mm cartridge into a bench-mounted AK rifle at Camp Chinen, Okinawa. “It completely blew up the receiver and the bolt was projected backwards,” Singlaub said, “I would imagine into the head of the firer.”


The first Eldest Son cartridges were reloaded with an explosive powder similar to PETN high explosive. The problem was that this white powder looked nothing like Chinese gunpowder, so if the NVA pulled apart an Eldest Son round it would be detected.  SOG’s technical expert, Ben Baker obtained a substitute explosive that so closely resembled gunpowder that it would pass inspection by anyone but an ordnance expert.

Think Like a Green Beret: Be Subtle

Read Next: Think Like a Green Beret: Be Subtle

Communist block 7.62 x 39 weapons such as the SKS, RPD and Type 56’s  could handle up to 40,000 p.s.i. of pressure.  The new powder produced 250,000 p.s.i. Enough to blow up the weapon and kill the shooter.

The secret lab in Okinawa developed more than just ammunition.  Tiger striped fatigues, Time Delayed fuses and Astrolite explosive (developed from NASA rocket fuel) all came from this small group of evil geniuses.

After the success in the lab, a specialized ordnance team was formed to process ammo.  Chinese AK bullets were sealed into steel cases with a thick coat of lacquer where the bullet entered the case. The rounds were pulled apart by hand and the powder was replaced with a high explosive substitute, then the bullets were re-seated and the ammo cans and crates so resealed just like the original. Pulling the bullet out left scrape marks, but when reloaded these marks were hidden by the case.

CIA ordnance experts also developed a fuse for the 82 mm mortar round that would detonate inside the mortar tube. Rounds for 12.7x108mm heavy machine guns soon followed.

While operating deep in enemy territory on other missions, Green Berets carried booby-trapped rounds and cases of ammunition cases with them and slipped them into the enemy ammunition supply chain whenever possible.


When an SOG team encountered an ammo dump, they would plant a case of Eldest Son ammo.  The 82 mm mortar ammo was not transported as loose rounds, but in three-round, wooden cases. The teams must have been very amused by the concept to put up with carrying a 28 pound case of mortar rounds in addition to all of their other gear.

When a SOG team ambushed an enemy patrol, they would load one round into an AK magazine or RPD belt left on enemy bodies with the expectation it would be recovered and re-used. When the gun later exploded, all the evidence of sabotage would be destroyed as the round was fired.


The rigged ammo turned up all over the battlefield, weapons exploded, killing riflemen and sometimes entire mortar crews, now it was time to initiate SOG’s black psychological operations exploitation plan.  The strategic objective was to aggravate the Vietnamese traditional distrust of the Chinese.  At the tactical level, individual soldiers questioned the safety of their Chinese-supplied arms and ammunition. One forged Viet Cong document spread rumors of exploding ammunition while another acknowledged ammo problems resulting from poor Chinese quality control.

Another forged document stated, “Only a few thousand such cases have been found thus far,” and concluded, “The People’s Republic of China may have been having some quality control problems [but] these are being worked out and we think that in the future there will be very little chance of this happening.”

Any NVA soldier, looking at ammunition lot numbers, would see that, due to the length of the supply chain, his ammo had been loaded years earlier. No fresh ammo could possibly reach soldiers fighting in the South for years.  The possibility of compromised ammunition would never disappear.


Military Assistance Command Vietnam (MACV) published Technical Intelligence Brief No. 2-68, “Analysis of Damaged Weapons.” It was widely circulated to U.S. and South Vietnamese units.  The study examined several exploded AKs, concluding they were destroyed by “defective metallurgy resulting in fatigue cracks” or “faulty ammunition, which produced excessive chamber pressure.” Enemy agents passed this information directly back to Hanoi.

American G.I.s were warned against using enemy weapons in public service announcements on Armed Forces Radio and TV and were duly monitored by the Vietnamese. . The Army Times warned, “Numerous incidents have caused injury and sometimes death to the operators of enemy weapons,” the cause of which was, defective metallurgy or faulty ammo.

Reports indicated that Eldest Son was working.  Forward Air Controllers observed mortars in Laos, Cambodia and even in Southern Vietnam blown apart in a star shape pattern. Usually there were a few NVA bodies present.

Planting Eldest Son munitions was not without risk.  On November 30, 1968, the helicopter carrying a SOG team carrying seven cases of Eldest Son 82 mm mortar ammunition was flying 20 miles west of the Khe Sanh Marine base.   It was hit by 37 mm anti-aircraft fire and exploded in mid-air with no survivors.  The remains of Maj. Samuel Toomey and seven U.S. Army Green Berets were recovered at the crash site 20 years later.

Despite the warnings, American soldiers fired captured arms, and at least one souvenir AK exploded, inflicting serious injuries. To avoid an ironic self injury, SOG stopped using captured ammunition in their own AKs and RPD machine guns and purchased commercial 7.62 mm ammunition from Finland.  This ammo, which SOG’s Green Berets fired at the NVA had been manufactured in a Soviet arsenal in Petrograd.  That particular bit of irony was appreciated.

In mid-1969, articles in the New York Times and Time, compromised Eldest Son.  The code name was changed to Italian Green, and later, Pole Bean. Ordered by the Joint Chiefs to dispose of its remaining stockpiles of ammo, SOG teams rushed to insert multiple missions on the Laotian border to get rid of the stuff before authority expired.

Even after the enemy was aware of the sabotaged ammunition, the program was psychologically useful.  The NVA could never again trust their ammo supply.  Radio intercepts confirmed the NVA’s highest levels of command had were disturbed by their exploding weapons, Chinese quality control and sabotage.

Project Eldest Son was a huge success.  Declassified reports reveal that SOG operatives inserted 3,638 rounds of sabotaged 7.62 mm, plus 167 rounds of 12.7 mm and 821 rounds of 82 mm mortar ammunition over the life of the program.

Like all great ideas, doctored ammunition of undetermined source is still turning up all over the world.

There are reports of a special thermite rifle round which melts in the chamber destroying the gun with no injury to the shooter.  This protects innocent users such as American G.I.s while denying weapons to the bad guys.

In Iraq and Afghanistan, most of the doctored ammunition is high-explosive 120-millemeter and 82-millimeter mortar rounds.  Like Eldest Son rounds, the fuses are altered so they explode inside the mortar tube, destroying the entire mortar system and crew.

The advantage of this particular sort of booby trap, its narrow targeting. Unlike rifle ammunition, which might readily pass into the possession of a homeowner keeping a firearm for self-defense, mortar rounds do not have a legitimate civilian use.

Green Berets like results and indirect effects can magnify the impact of their small numbers.  Projects like Eldest Son will continue in the future conducted by friend and foe alike.  It pays to know the source of your ammunition.

(Featured image courtesy of shadowspear.com)

Article originally posted on Loadoutroom.com