i've always been partial to old skool .30 cal myself.. M14 etc..
http://news.yahoo.com/s/ap/20080529/ap_on_re_us/army_chief_bullets
http://news.yahoo.com/s/ap/20080529/ap_on_re_us/army_chief_bullets
Current and former soldiers interviewed by The Associated Press said the military's M855 rifle rounds are not powerful enough for close-in fighting in cities and towns in Iraq and Afghanistan.
The M855 rounds were designed decades ago to puncture the steel helmets of Soviet soldiers from hundreds of yards away. Some soldiers said that they are not large enough to stop an enemy immediately in close quarters.