If range and accuracy are the primary concern, they would be better off with a 6.5mm. Hell, they could just neck down 7.62 NATO. Flatter trajectory, way more effective range, and better penetration in the same size package.
7.62 is really the wrong answer to just about any problem the military has these days. Like the 9mm, the only reason it is around is due to legacy issues. There are reasons those cartridges have been dumped in various times and places. We don't need to move backwards, we need to move forward.