So now you're comparing .44Mag data to .454Casull??? Yeah, dummy, you increase powder capacity even further and run at the same pressure, it's rather intuitive that velocity is going to go up. Linebaugh wrote the same sort of nonsense. Only problem with that is that the .45Colt can't run at the same pressure unless it's in a five-shot or a Redhawk. How about we actually compare the two cartridges in question instead? With the velocities I recorded from actual guns with 4 5/8" barrels in parenthesis.
In Hodgdon's data, the .44 gets 100fps higher velocity. In my testing, the .44 got 70fps higher velocity. So apparently, that added pressure is actually doing something. You're an idiot if you think that the .45Colt handles heavy bullets better, or handles heavier bullets. It doesn't. Fact, not opinion.