designed to shoot a particular bullet weight well, the .44 magnum for example was designed around the standard 240 gr. bullet.
As times progressed someone thought if 240 is good 300 or bigger must be better. At some point I feel you reach a point of diminishing returns. In my .44's I stay between 240 and 255 gr bullet weight and between 300 and 325 gr. weight in my .454. Do you have a preference for your guns?