There are many fine deer calibers out there but of the 2 you mentioned Greg, I would go with the .270. Either the .270 Winchester or the new .270 short mag would be an excellent choice for a deer rifle. I personally use a Browning A-Bolt in .270 Win. and it performs flawlessly with 150 grain Nosler Ballistic Tips. I have dropped whitetail bucks from 20 yds out to 300 yds. with it and don' t personally see the need for more gun. But if you anticipate longer shots than that then you might want to look at the .270 short mag.......either way you won' t go wrong.