The US Gov has been testing several new concept rifles as a replacement. As I understand it, the newer M16s and M4 are just plain ole hard to beat. That is why they are still around. Here is a H&K prototype replacement that wa eventually canceled:
<a href="http://s57.photobucket.com/albums/g239/dbpen/?action=view¤t=BootsFR.jpg" target="_blank"><img src="http://i57.photobucket.com/albums/g239/dbpen/BootsFR.jpg" border="0" alt="Photobucket"></a>
Never Suspect Malice When Stupidity Will Suffice
Spray and Pray because Happiness is measured in Rounds per Minute!