BeardedBruce, the M-14 issued to the US Army was semi-automatic. I know. I carried one. I would have known if it were capable of automatic fire. The fact that removal of a selector shaft lock, addition of a selector switch and changing an internal part of the receiver converts it into an automatic weapon doesn't mean that all M-14s were automatic weapons. The automatic version was only issued on a limited basis as a squad automatic weapon (SAW). The following is copied from this site:

The M14 rifle has been employed as a battle rifle, squad automatic weapon, competition match rifle, grenade launcher, sniper rifle and ceremonial rifle. As a battle rifle, the M14 has seen service from the 1963 Cuban missile crisis to 2002 Afghanistan. In the U. S. military, the selector shaft lock is installed on most M14 rifles so that only semi-automatic fire can be employed. In the U. S. Army infantry squad of the early 1960s the M14 rifle was standard issue. Each ten man infantry squad had two automatic riflemen and two grenadiers. The M14 rifle assigned to the automatic rifleman had an M14E2 stock and sling, stabilizer assembly and M2 bipod. His rifle would have a selector switch and selector shaft spring installed in place of the selector lock. In this configuration, the rifle was designated as the M14E2 in 1963 and redesignated as the M14A1 in April, 1966.