"Something else important is weight. The 5.56 round is WAY lighter than a 7.62 round, and carrying a full load of ammunition is much less a burdon"
Thats a myth that has been disproved countless times. There is no weight savings. Infantry soldiers typically carry 100 lbs of gear wether they have 308 or 556 rifles. I have heard the "weight saving" thing before, its bunk.
"Im sorry, but giving our troops a .308 rifle to raid houses with would be overkill and a tactically unsound decision. There would be much more collateral damage from wall penetrations and our troops might get into close quarters trouble without a decent rate of fire. I'd rather have an M16 to clear a room than a M14."
Again, I have to disagree. For starters, you dont issue rifles to your troops to reduce collateral casualties. That sounds unfeeling, but their job on the battlefield is not to be nice. Its to kill the enemy. Period.
As for rate of fire, you can clear rooms with M14s, grenades and pistols, just as you can clear rooms with M16s, grenades, and pistols. Also, troops have supporting Squad Automatic Weapons, like light machine guns, ect. You would not want to be an insurgent in Iraq when a section of infantry came in with 6 M14s, and 2 M249s, and grenades, with the intent to send you to the afterlife.