Check out the M16 training video that the Air Force showed troops heading to Vietnam.
The M16 is one of the most iconic military rifles. Whether that is a good thing or bad thing depends on your personal opinion.
Regardless, this Air Force M16 training video from 1967 is still a fascinating look into the past.
The M16 did run into a lot of problems in the jungles of Vietnam. It was known to jam and malfunction frequently unless the rifle was kept very clean. That was an almost impossible feat to achieve in the wet, muddy jungles of Vietnam. However, it also led to the development of the wildly popular AR-15 platform.