I don't do turrets, so with a normal hunting reticle I would go about 400 yards using a hold over of 18" to 20". From the targets I have shot at that range on a still day I would be OK, with a slight breeze a 10 shot target pattern grows horizontally about 8" wide.
With a Leupy B&C reticle with the 450 yard dot and 500 yard cross hair I would go that far, but not 600. Also if the breeze was fairly steady, the B&C windage lengths of their graduated cross hairs would be helpful.
If the breezes are gusting, I would only go about 350 yards.

The reason I wouldn't go to 600 even in perfect conditions is I don't have anything that will hold a tight enough group at that distance.