OK if we insist on a real comparo, here ya go
460 Weatherby magnum-450 Barnes x
Energy
Muzzle 100yds 200yds 300yds 400yds 500yds
7284 6333 5482 4725 4050 3452
Velocity
muzzle 100yds 200yds 300yds 400yds 500yds
2705 2518 2343 2175 2013 1859
243 Winchester -100gr corelokt ultra-bonded
Energy
Muzzle 100yds 200yds 300yds 400yds 500yds
1945 1629 1356 1120 917 745
Velocity
2960 2709 2471 2246 2033 1832
so you see, the 243 has as much velocity as the 460 does at 500 yds which means it hits harder and kills more efficiently.