One of the new AR15 with .300 AAC Blackout munition, maybe. But there are some really good rifles out there and, especially of the 6mm breed. Beretta has the ARX-160, IMI and the Tavor is a awesome, the Russians have the A-545/A-762 which solves the AK's recoil issue.

In general it is a bold statement to claim something to be the best with so many new options out there.