Can't go wrong with a 25-06 for antelope, but if you want a light weight rifle also take a
look at the Remington 700 LSS Mtn. rifle (laminated stock with stainless barrel/action).
It's available in .270 Win. which is never wrong out west for antelope or mule deer.
Rifle weight is just 6-5/8 lbs. I'd put a good 2-7x or 3-9x Leupold on it.

Of course, if you really want to have fun take a 30-30, and try stalking within about
50-75yds of 'em. It can be done, I know because I did it many a time when I lived out
in Wyoming. Or, you can lure them in too. Pronghorns are some of the most curious animals around. Your .243 is all you really need, but then again we all need an excuse now & then for a new rifle.
Good luck.

ps: If you try crawling around thru the sage brush to get close be sure to watch out
for the rattlesnakes. Other than that, have fun!