30-06 is the same diameter as 7.62 / .308 but a much larger casing with much more power. Depending on bullet impact site, it's either going to tear a hole through a large amount of soft tissue, or transfer a huge amount of kinetic energy into bone. I suppose depending on the part of the skull it, it could remove the head or just blast a hole through it. In the case of Kirk, while I didn't see the video from what I understand it entered in the neck or upper collarbone area at the neck. Mostly soft tissue, from the sound of it. Also, a 30-06 hasn't lost a lot of energy at 200 yards, in terms of soft tissue damage.