  ==most powereful before the .357 mag? absolutely not!== There's no citation for this claim, which isn't suprising since it isn't true. The .577 pistol cartridge is rated at 525 on the kynoch charts(factory load: this was used in various pistols), and the bulldog pistol also fired a more powerful round. There are probably others as well, these are some examples I just happened to remember.   