I agree that the 270 win loaded with a quality bullet,
is about ideal on deer size game, and I've used it to kill one elk.
people that feel their favorite cartridge is vastly superior to something rather similar,
, in my opinion, tend to lack extensive out in the field time.
those cartridge comparison discussions might be fun,
but they are more useful in starting arguments than in any documented increase in your potential success.
that fact and the fact that most hunters are very bad at range estimation, past that 250-300 yard distance,
and decades of seeing guys claim 500-600 yard kills while having nearly zero knowledge of the rifles trajectory,
and knowing they sighted in dead on at 100 yards makes most of those stories rather dubious.
I've used a dozen or more rifles in cartridges like,
270 win,
30/06,
300 wby
375 H&H,
340 wby ,
45/70,
358 win,
257 roberts,
and 35 whelen etc
If the person carrying that rifle understood its trajectory and its potential limitations, and the anatomy of the game,
he found that with proper shot placement, and projectile they all worked just fine.
one gentleman, I hunted with for decades exclusively used a Winchester mod 70 pre-1964 in 257 roberts
used to constantly kid me about my use of a 340 wby that weighted several pounds more than his rifle and obviously kicked a great deal harder.
we both killed our share of game .
anyone who is a decent shot , and who understands both his equipment limitations and the anatomy of the game,
can use almost any centerfire rifle, with proper ammo and be successful.
BTW if your current rifle is not giving you the desired lethality, you might consider changing the projectile your using, it can make a huge difference.