RE: Please help - I am looking to get a new deer rifle for mule deer and antelope-
a .270 will be effective downrange as far as most of us need to shoot (out to 400 yds). I shoot a .270 WSM and the ballistics are a little better than the .270, but I think it may be a little overkill. The big magnums will have better knockdown at distance, but the average guy will tend to be bothered by the recoil enough for it to affect their accuracy. And accuracy is the most important factor when shooting longer distances. If you can handle a 300 WM, then shoot it. Getting familiar with your .270 and how it shoots downrange will produce just as well, as long as you are comfortable with it.