RE: Longest range?
IF the person shooting is up to the task the 30-06 is capable of taking an elk to 500 yards of so.
Does this mean that we should all go out and shoot at elk 500 yards away? Heck no. But an extremely skilled marksman under the right conditions could take elk at that distance.
Personally I won't take a shot past about 300 yards with the 30-06 unless it was laser ranged and If I had been practicing I would extend that to about 400 yards.