Unfortunately, he, like many others, abandoned the .44Mag before there were any decent heavy bullets or data available. Everything "claimed" that the .45Colt will do better, the .44 will beat by 50-100fps.
Ross was using a heavy SSK and two NEI Keith bullets, 315 and 325 grains in the 44 Mag, at the time in Africa. He detested the SSK, a pointy affair.
By all accounts, his five shot Seville would exceed a factory made 44 by a wide margin and did.
Loaded to the same pressure with the same weight bullet with the same nose shape, the 44 will have the potential to penetrate better due to less displacement and greater SD, while the 45 Colt will have more displacement and greater velocity, due to more powder capacity, the same way a 44 can kick a 250 faster than a 41 can, at the same pressure...
