After firing M14’s for a while at a rifle range, a DI showed the benefit of the new M16 recoil reduction by putting the stock on his chin and firing a few rounds before the “tour” group then got a turn with it to hit some targets.
Qualified with the M-14 in 1969, first fired the M-16 in 1970, last fired it in 2010 (break in service). Hated the M-16 & still do, lousy kachingka aluminum toothbrush. AK-47 in Vietnam had it skinned a mile.
Bought an M-14A after I retired, love firing it, the rifle equivalent of my living room couch.
Our introduction to the M-14 was watching the drill sergeant fire it from his chin.
We had a DI brace it against other parts of his anatomy...
They must have brought her out just for the occasion. I don't think I saw her again during the training cycle (wherein some coursework was attended by the BT BN en bloc including the company of female recruits and their scary bull-dyke-lookin Drills).