"Well at least they gave them something better than the darned M-16 variants."
'Apples vs Oranges' IMHO
The M-14 is well suited for the open landscape of Europe(originally designed to fight in that theater). It was too heavy and less suitable for the short range jungle combat of the SE Asia theater which birthed the 'spray and pray' M-16. The long ranges of the Middle East brought the M-14 out of mothballs to send it's bullets across the longer ranges and open ground of that theater.
When I was intimately involved with the M-14, it was considered a 'middle ground' spotter's rifle(longer range capability than the M-16 but less than the bolt rifle). It was heavy and somewhat unwieldy in the thick jungle but I was young and strong so didn't notice as much. It would have been much more noticeable if the helo had not replaced boots for most of the movements.