[ARCHIVED THREAD] - M4 Barrel

Posted: 3/29/2009 3:57:57 PM EDT

What is the real purpose for the undercut in the M4 barrel? I bought my first AR this weekend

and didn't get the M4 barrel. I wanted a flat-top M4 with flip up sites but none of the M4's were configured the way I wanted. I ended up going with a standard flat top RRA upper with a flip up front site. It was cheaper than the M4 configuration anyway.