Max effective range for the .308 is 700 yards. The reason for that is the bullet is not heavy enough, or traveling fast enough at that range to carry a stable trajectory. The shorter the barrel, the less the muzzle velocity. That will shorten the effective range further.
If you truly want to shoot a minimum of 600yds, go with the 300 win mag.
ss
If you truly want to shoot a minimum of 600yds, go with the 300 win mag.
ss