Corbon performance. The .45 has both 60% more frontal area and a much larger diameter hollowcavity. So it's a lot less likely to fail to expand in flesh. That failing was the reason for the development of the 125 gr jhp for the 357, you know. yes, you can get the 158 gr 357 jhp to 1400 fps, but then your split times, for repeat hits, go to .50 second,instead of .35 second (with the 125 gr load) too. With the 160 gr .45 load, splits run .18 second, so dont be stupid and take 2-3x as long for repeat hits,or for hitting other attackers.