In 2008 and 2009 I shot (8) mule deer between 329 and 510 yards.
All were with the same 270.
I have rifles I could shoot a deer with in; 19 Badger .222,.223, 22-250 .243, 6mmBR,.243Win,.250/3000, 257 Roberts Ackley, 6.5 jap, 6.5x55, 270,7x57mm, 7mm Rem mag, 30-30, 303Sav, 300Sav,.308, 30-06, 300 Win Mag, 300RUM, 7.5 French, 7.5 Swiss, 7.62x39mm,303Brit, 7.62x54R, 8x57mm, 338WM, 35 Whelen, 44 mag, 45acp, 45Colt, and 45/70.
I think that choosing the rifle faces a number of trade offs, and weight, range, accuracy, and killing power are up there.
I can't think of a cartridge that is markedly better than the 270 for hunting deer.