General Discussion
In reply to the discussion: One Photograph, Two Bullets, And 26 Reasons We Need To Take Action For Newtown, Connecticut [View all]sir pball
(5,341 posts)Here's the four most common rifle rounds the military uses:

The one on the left is the .223/5.56mm. The next one in is the .308/7.62mm, which the 223 was implemented (not designed - the original concept was a civilian varmint round) to replace - the 308 was just too big, heavy, and kicked too hard for the average soldier to handle. It's widely considered to be one of the best medium-game rounds ever designed, packing over twice the power of the .223 - which should give pause to the idea of little guy being any use for hunting.
The other two are what the military considers "high-powered" rounds, used in long-range sniper rifles - .300 Winchester Magnum and .338 Lapua. The former is just as popular a sporting round as the .308; it was developed in the civilian market before ever being militarized.
So yeah. The .223 is, even by military standards, extraordinarily underpowered, and it was quite deliberately designed that way.