130g Nosler partitions from my .270 always seemed to kill elk pretty dead for me. I know many others who would say the same.
Were I starting from scratch, would it be my first choice as an elk-only rifle? No. But it kills elk dead, especially if you're confident with it. As always, shot placement and knowing your limits matters much, much more than choice of .277 vs. .308 (or bigger) caliber.
BTW, if you search a bit, you'll find pages and pages of debate on what will or won't work for elk. Or, it might just get repeated here in the days to come...
Dave
