So it seems. Looking into it, the Scottish m/e requirement is 1700 ft lbs. - comfortably exceeded by the .50cal round ball at a tad over 2000 ft lbs, but NOT in the velocity stakes of 2450 fps....
As ever, I'm guessing that we are beholden to the whim of a chair polisher or three who wouldn't know a foot pound from a trumpet.
Whinemeal, thanks to all so far who have taken time to respond to my genuine request for information.