The usefulness of assault weapons has been studied.

Are such weapons effective?

What caliber is most effective?

They ONCE had studies in Nam which studied the 223 and said it was more lethal than a 7.62 caliber!!

Recent studies and experience suggest that the varmint caliber is not the "killer" wanted.The 6.8 is under evaluation as a superior round!! Hunters could have told them that by its ballistic features.

The M4 is being refined further by HK into a more reliable,maintenance free firearm!!

A good reference--

http://en.wikipedia.org/wiki/Assault_rifle