bellydeep,
I don't know who the writers were that claimed Milek mostly (or only) used head and neck shots, but I remember reading other articles by him back then mentioning lung shots on elk with the .25-06.
I've been around a few elk taken with lung shots with various .25 caliber cartridges and they all died pronto, whether the bullet passed through or not, though most of them did. In fact the only .25 caliber bullet I've seen recovered from an elk was the Barnes TTSX 100-grain my wife killed a cow with last month, using a .257 Roberts, but that was a quartering-away shot, not broadside. Have seen the 100-grain Nosler Ballistic Tip exit on a broadside cow elk, from a .25-06.
The older guy who delivered our newspaper when we first moved to this area 24 years ago used a .25-06 on elk. He eventually found out what I did for a living and one day showed me the remains of a .25-06 bullet that failed to penetrate the shoulder of a spike. He wondered why it happened, and I asked him what ammo he used. Turned out it was a 90-grain varmint load! But it also turned out that he'd killed the spike with a second shot, behind the shoulder, which is how he recovered the first bullet.
