Slamfire: that’s an excellent “grouping” of videos!
Aside from the bullett debates between those cartridges, despite the extra weight of the M-14 (also the ammo) VS the M-16, the unused potential of the M-14 for our soldiers must have been huge, regarding both reliability and penetration of various types of cover.
Being of the right age and pulling a lot of Highpower Rifle targets with Vietnam veterans, feelings about the M16 depend on when the solider received the weapon. Early M16's were jammatics and the guys who got them did not like them for their unreliability. But, the guys, 1968 on-wards, did not have strong feelings for the M14 or the M16. It was just another thing they were given and had to lug around. One bud did say, the combat load with an M16 was 400 rounds, but it was 200 rounds for the M14. And he had shot 400 rounds in a day, and preferred the more bullets options.
It was very discouraging to talk to Marine MSgt Polk about the value of NRA Highpower. MSgt Polk was a veteran of the Korean and Vietnam War. MSgt Polk had a trained combat dog and was assigned to protect an Army unit in Vietnam. The Army unit commander walked over a bobby trap that killed himself and severely wounded MSgt Polk! MSgt Polk had been there and done that, and thought NRA Highpower was of little or no use in combat because you fired at tree lines or shrubbery. It was extreme rare for Vietnam grunts to see VC or NVA living or dead. The Vietnamese carried their dead off, and blood trails were more common to find than dead Vietnamese. They received incoming from tree lines and heavy foliage, and they fired back at tree lines and foliage without ever seeing how the target reacted. So, they seldom saw the extra penetration, or needed the extra range, of the M14. And once the major problems of the M16 were fixed, it was just another gun.
This was a war story I was told. A Vietnam veteran saw a Vietnamese man, encased in bamboo armor, and carrying a bamboo spear, attack American's manning a M60. The spear carrying man got one American before the machine gun finished him off. That was one brave and determined individual. Before he charged, he knew he was going to die, and was only concerned in killing as many Americans as he could, with his spear, before he died. Determined individuals are hard to kill.
A bud, his son was a battalion scout sniper in Iraqi. Son was not impressed with the M4, said Iraqi's shot with it "did not stay down". But Iraqi's shot with a scope M14 did. Different war, and different observations.