In my opinion, the very best 7.62X51 calibre fighting/sniping rifle is the Knight's Armament Co, SR-25.
16" or 20"?
Makes me wish U.S, Navy SEALS had access to a piston driven CQB-16 type SEI in a Blackfeather "RS".
In collapsible form it's lighter than the 10.2 Lb. 16" SR-25, but it would weigh about the same if you made it a folder.