RE: Antelope Bullet for .243?
The .243 is perfect for antelope. Rather than get too tied up considering which bullet, I recommend that you find something that your rifle shoots well and use it.
Most of my antelope hunting was done before I started reloading and none of this fancy custom ammo was available. The order of the day then were standard, 100 grain CoreLokts, PowerPoints, and Hi-Shoks, all of which my rifle seemed to shoot well and always brought home the venison. But, I'm aware of people using 80 grain bullets and having problems, though I can't attest to whether it was their shooting or the 80 grain bullet not being optimal for big game. I'd stick with the heavier bullets.