You don't need anything more than a 7-08 out to 600yd. A 308 would do just fine at that range as well, for hunting or target shooting. 6.5cm won't give you much advantage over 7-08 with a 168gr vld at that range, if any. Using a 308 will make you better shooter as well. I would even recommend 223 with a 75-77gr bthp for 600yd target shooting.
If you don't reload then 308 is what you should use; there will be more match ammo options than 7-08.
If you don't reload then 308 is what you should use; there will be more match ammo options than 7-08.