I carried an M-14 in basic training in 1966. As I recall, you had to have a special tool to change an M-14 to full auto. We were never issued any such tool. M-16 was all I ever carried that only required flipping a switch to auto-fire.
BATFE are just another collection of JBTs who prefer a disarmed public; of course, smuggling illegal weapons to Mexican drug lords, well, that’s another story.
Truth bump!