That's the old addage of soft bullets being upset by too much velocity, resulting in less penetration.
The old timers shot their .404J's and similar at around that speed, evidently with good results. Then those rounds were bumped to 2,400 or so, presumably using slightly tougher bullets for more knock down power.
Pushing the 9.3x62 to 2,600+ fps, bullets like the 250 NAB and 250 TSX come into their own. Same idea with the various .375's.
DF
