Since we're still stuck on pressure, let's look at what that extra 6000-10,000psi actually yields you. With the .44, you can drive bullets the same sectional density (330gr .44 vs 360gr .45) 150fps faster and get a little more penetration. Or you can drive the same weight bullet (330gr .44 vs 335gr .45) at the same velocity and get a lot more penetration.