the skill and experience of the guy holding the rifle and his knowledge and acceptance of the rifle's limitations and knowledge of game anatomy is the deciding factor.
having faith in the rifle you carry and the skill to use it quickly and with consistent accuracy is critical not the head stamp.
Id strongly suggest you use a rifle that can put a minimum of 150 grains of bullet weight and about a minimum of 1500 ft lbs at impact energy on the target at the ranges your likely to hunt.
my partner for 35 years used a 358 win BLR with zero problems, he used speer 250 grain bullets,
I never saw him take a shot over 250 yards
one of the older guys in camp used a 257 roberts , winchester bolt action,
with 100 grain speer bullets he collected several elk in that same 35 years but he was smart and never took shots over about 200 yards,
any 270-30/06 with a decent high quality bullet , and proper shot placement will work,
now thats certainly not suggesting some choices are not significantly better than others.
over 4 decades,
it became all too obvious that elk are not bullet proof and a well placed shot is lethal,
and caliber is not as critical as you might imagine. the critical part is that finding an elk and making that single precise shot placement
I used a 340 wby with a 250 grain bullet or a 375 H&H with a 270 grain bullet on most hunts, I never had any problems dropping game either.
I have the skills to make longer range shots but rarely exceed 300 yards , simply because where I hunt shot range over 200 yards were and are rare
most of the old geezers I hunt with have decades of field experience and the 30/06, 308 win, 338 win,358 win, 35 whelen and 450 marlin are all rather popular
heres a link to a ballistic calculator
http://www.shooterscalculator.com/ba...tory-chart.php