I trained on the M-14 and a few years later was given a course on an M-16 as I had my over the pond orders albeit never went. From my limited knowledge the M-14 was designed as a longer range weapon to defend fixed positions in Europe. The M-16 came along as a more rapid fire closer in weapon which allowed a soldier to carry more rounds. I own ARs in both 308 and 556 and would say the calibers of each fit their billing exactly. So, given our need for a longer range rifle with great knock down power at long range needed in Afghanistan, I would opt for the M-14 or any other 308 rifle deemed OK.
As a side note, there was a story this week that due to ROE in Afghanistan, soldiers in some areas patrol with empty firearms. Now, whether one has a 556 or 308, such rules are beyond the bounds of logic. The nitwit responsible for promulgating them should be fired.
Sounds good to me!