What's with the M4, when you already listed HK416? They're essentially same gun, the latter having better reliablity though.
And Beowulf??? Geez, that M4 variant is barely heard of, much less used by any professional army. There are other M4 variants out there that are far more inventive and funnier than a .50 M4, e.g. chainsaw:http://i392.photobucket.com/albums/pp2/Xen...1162009-006.jpg
Seriously, I'm contended with the Graw2 arsenal as-is. Rather than throw in a whole bunch of guns, they should put their focus on balancing and realistic-ize those guns they have been using through out the franchise.