Which poorly designed military product caused catastrophic failures during the Vietnam War, leading to widespread modification in the field by soldiers?

Throughout military history, weapon and equipment design has been critical to battlefield success. From early innovations like the English longbow to modern stealth technology, product design has shaped warfare outcomes. This poll tests your knowledge about a famous product design failure that impacted military operations during a crucial historical conflict. How well do you know the intersection of product design and military history?

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The M16 rifle, which initially jammed frequently due to its direct impingement system and ammunition issues
The Bell UH-1 'Huey' helicopter, which required constant rotor redesigns due to failures in high humidity
The M113 Armored Personnel Carrier, which overheated consistently in tropical conditions
The PRC-25 field radio, which had fatal signal interference problems causing communication blackouts