RE: 270 elk range???
When I used a 270 win for bigger game (moose and elk) my personal limitation was 250 yards positive vital shot max. Of course as important is picking the right bullet for the task in the first place. With a solid constructed bullet such as: TBBC, Failsafe, NP, Barnes, etc. If you know your abilities and more so can maintain them in the heat of the moment the 270win is capable to handle elk without question.
I however wouldn't suggest a max range to another hunterthat I have no clue what abilities they possess..sorry you'll have to figure that part out on your own! Just be realistic/honest with yourself& you'll be alright.