if the velocity is the same--a 180 graine 40 or a 180 gr 45, than the energy is the same
what is different and can be discussed is, the diameter of the 40--being smaller it may not tick the vein that the wider
45 cal does. but the 40 goes deeper and may do damage the 45 can't reach.
same as arguements 9 vs 45 have raged for over a hundred years...
and it not for lack of bodies to examine that the discussion continues.