4. Critical Failure

The first generation of M-16 rifles was introduced to the US Army with high expectations. However, these rifles soon became a source of frustration due to their frequent malfunctions, including jamming and failure to fire during critical moments in battle.

This reliability issue was so severe that American soldiers, finding themselves at a disadvantage, began to prefer the robust and dependable AK-47, the preferred weapon of their Vietnamese adversaries. Consequently, US soldiers often resorted to using AK-47s picked up from fallen Vietnamese fighters.