A tidbit o the AR-15/-16 story.
If you find back copies of the National Geographic magazine from the early 1960s look for the issue spotlighting the USAF.
While there were loads of excellent photos of aircraft and people there is one that caught and kept my attention. It showed a line of Air Commando NCOs dressed in fatigues wearing their official Aussie-style hats (fold-up brim). The caption said they were on a small arms firing range shooting their AR-15 rifles.
This was a few years before wide-spread involvement in Viet Nam.
Just an interesting historic photo from the past.
Were they semi-auto or full-auto versions?