Moose,

I'm guessing that you're planning/thinking about an antelope hunt next year? Don't worry about your 30-06, it's plenty good enough for those prairie goats. I lived/hunted in Wyoming for near 7years, and I got by just fine using either my 243Win. or 308.

Yes, antelope can be seen at very long ranges, and some are even shot at very long
range ( over 300yds to 400+ yds.). But, most can be taken within a couple hundered yards. Most of mine were shot within 150yds., and the longest shot I ever got on an
antelope, or anything else out there for that matter, was approx. 225yds.

Use a good accurate load with 150gr. or 165gr. bullet, and sight in approx. 2-1/2" to 3"
high at 100yds. Then practice - practice shooting at longer ranges, and doping the wind.
Wind is the biggest challenge/problem. That's why I always liked to stalk 'em, and get
as close as possible. Learn where your rifle/load hits at the extended ranges (300 & 400yds.). Know your bullet drop - don't just guess from some ballistic tables.

And, switching to a 270, etc. isn't going to make enough difference in trajectory to matter. Look at some of the ballistic tables - the difference in drop out to 300yds. is just
not that much between these rounds. If you feel you must have something flatter shooting, then I would have to suggest going to a 7mm Rem.Magnum. It will flatten the
trajectory. Or, too, a 270WSM. But, IMHO, the magnums are not really needed.