Check this out...a outstanding documentary:
This can be found on YouTube cut into about 10 sections; I saw it years ago & found it very good:
http://www.imdb.com/title/tt0169885/board/threads/
The documentary film-maker spent about 97 days attached to a Marine Rifle company from the 7th Marine Regiment with his film crew; both he & several members of his film team got wounded; can't exactly tell when it was filmed but the Marines STILL have M14s & 3.5 in rocket launchers so I imagine it's early 1967.
NM