Know Where Your Ammo Comes From! Project Pole Bean: How Sneaky Green Berets Blew Up a Few Guns and Frightened an Entire Army

In 1968, American troops in Vietnam reported scattered incidents where dead NVA soldiers were found with parts of their exploded rifles protruding from their skulls. Technical Intelligence attributed this to poor metallurgy and bad ammunition. The situation was a little more complicated than it appeared.

My uncle Harvey was a Green Beret who served with MAC-V SOG in Vietnam. When I was a kid, I pestered him to tell me about their missions. They would go deep into the North Vietnamese Army (NVA) base areas and tap communications wire, take prisoners and do bomb damage assessment.

My favorite story was how they used to carry in ammunition and put it in NVA storage bunkers. Well, to be accurate, they put it BACK in the bunkers and some other places too.

Military Assistance Command Vietnam’s Studies and Observations Group (SOG) 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 and 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 warfare pro. He parachuted behind German lines with the OSS in August 1944 to fight with the French Resistance fighters supporting the D-Day invasion. 

After WW2, 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 and led troops in the Korean War. He was the perfect guy to run SOG.

SOG teams ran deniable missions into Laos and Cambodia to gather intelligence, wiretap communications, kidnap personnel, ambush convoys, raid supply dumps, plant mines, and generally spread the joys of unconventional warfare across the NVA rear.

This may not sound as romantic as fighting front line infantry units, but without a secure rear, the bad guys at the front got less food and ammunition. As these operations began to effect NVA operations, several divisions of NVA regulars were put on security missions along the Ho Chi Min trail.

Special NVA units were formed and specific tactics were developed to find and kill SOG teams. Landing zones were watched, trackers and dogs were deployed, and a system of communications established to allow a rapid response to any contact with SOG. While finding the NVA could be a problem for infantry units, they trucked guys in for the SOG teams to mow down.

While skulking around, these teams often encountered ammo caches with millions of rounds.  Being Green Berets, their 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 take some of the ammo, booby trap the individual rounds of ammunition, and give them back.

Like most unconventional tactics, ammunition sabotage was nothing new.  In one well-documented operation, the British slipped exploding rifle cartridges into enemy caches during the Second Matabele War (1896-1897) in what is now Zimbabwe. The British scouts were led by an American, Frederick Russell Burnham, who probably put them up to it.

During World War, the British Special Operations Executive (SOE) and American Office of Strategic Services (OSS) collaborated on Operation Natterjack to plant sabotaged ammunition in the Japanese supply chain. OSS Detachment 101 distributed the ammunition in Burma but little is known about the results.

The SOG ammunition enhancement plan was briefed all the way to the Joint Chiefs of Staff in the Pentagon. On August 30, 1967, they approved the plan and two weeks later, Singlaub watched a CIA technician load a sabotaged 7.62X39 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 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 altered 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.

Communist block 7.62X39 weapons such as the SKS, RPD, AK47, and Type 56’s could handle up to 40,000 p.s.i. of chamber pressure. The new powder produced 250,000 p.s.i. enough to blow up the weapon and kill the soldier shooting it.

The secret CIA lab in Okinawa developed more than just rifle ammunition.  Tiger striped fatigues, Time Delayed fuses and Astrolite explosive (developed from NASA rocket fuel) all came from this small group of evil geniuses. Later CIA ordnance experts developed a special fuse for the 82 mm mortar round that would detonate inside the mortar tube. Rounds for 12.7x108mm heavy machine guns soon followed.

After the process was developed in the lab, a specialized ordnance team was formed to modify the 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. The bullets were then re-seated and the ammo cans and crates resealed just like the original.

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. If the SOG team encountered an ammo dump, they would plant a case of doctored ammo. 

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 NVA 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.

The 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. 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 a Technical Intelligence Brief titled “Analysis of Damaged Weapons” which 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 which were duly monitored by the Vietnamese. The Army Times warned, “Numerous incidents have caused injury and sometimes death to the operators of enemy weapons.”

Mortars work by using a low pressure charge to throw a bomb with a fragment producing case down range. There is a firing pin in the bottom of the tube which hits a primer in the mortar round when the round is dropped in the tube. A fuse ignites the main charge when it hits the target. The modified fuse blows the main charge inside the mortar tube.

As the rigged ammo spread through the system, 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 3-4 NVA bodies present.

Planting munitions was risky. On November 30, 1968, a helicopter carrying a SOG team with seven cases of CIA modified 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 ironic self-injury, SOG stopped using captured ammunition in their own AKs and RPD machine guns and purchased 7.62X39mm ammunition from Finland. This ammo, which SOG’s Green Berets fired at the NVA had been manufactured in a Soviet arsenal in Petrograd. Thank you, Comrades.

To keep it secure, the code name changed through the course of the war. The Project began as Eldest Son, then was changed to Italian Green and ultimately Pole Bean.

In mid-1969, articles in the New York Times and Time magazine compromised the mission. Ordered by the Joint Chiefs to dispose of their remaining stockpiles of ammo, SOG teams rushed to insert multiple missions on the Laotian border to get rid of the stuff before their 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 were disturbed by their exploding weapons, Chinese quality control, and sabotage.

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, this one has been copied. Doctored ammunition of undetermined source is still turning up all over the world. There are reports of a special thermite rifle round that 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.

Former Green Beret Jack Murphy, author of “Murphy’s Law”, tells the story of attempting to shoot a captured SVD in Iraq. The primer popped and the round got intensely hot melting the chamber and barrel together. No need for fake Technical Intelligence Bulletins to protect friendlies here.

In Iraq and Afghanistan, most of the doctored ammunition is high-explosive 120-millimeter and 82-millimeter mortar rounds. Like SOG 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 is narrow targeting. Unlike rifle ammunition, which might turn up with a homeowner keeping a firearm to protect his family, mortar rounds do not have legitimate home security use.

While it is gratifying to see the direct results of your efforts, it can be more effective to set the conditions for success and then stand back and watch the enemy do the work for you. The results from Eldest Son, Italian Green and Pole Bean exceeded all expectations.

Green Berets are trained to anticipate the second and third order effects of their actions. These projects killed hundreds, frightened the entire North Vietnamese Army, and sowed distrust between Vietnam and China at the highest levels of government for years to come. In 1979 the two countries went to war.

It pays to know the source of your ammunition and where it has been before it got to you.

Buy and Sell on GunsAmerica! All Local Sales are FREE!