I've killed one antelope at 420 yds with a 105 Berger from a 243.
Can't imagine needing more gun.
Might want to add that the 105 is a great bullet, but some
243 barrels won't stabilize it. Even Berger cautions against using it with a 9 twist, which is the norm with most 243s. Not always
the case .... but usually.
If you're getting good accuracy with a 9 twist consider yourself fortunate.
Our 243s are 9 twists and neither will shoot the 105s with any consistency.
If a rifle won't stabilize the 105s, the 95 Classics are excellent, and are plenty of bullet for antelope.