I prefer the "premium" 147 grain loads because I believe a handgun projectile, especially a relatively small diameter handgun projectile, should have as much mass as possible to offset the possibility that it will not expand properly. Besides, a bullet that size moving at roughly 1,000 fps is nothing to sneeze at.

I doubt that the "transition" from 9mm to .40 had as much to do with the perceived ineffectiveness of the 147 grain 9mm loadings as it did with achieving near .45 ACP level performance from a 9mm platform (with the original 180 grain .40 loadings).

The truth is that all of those gelatin tests look so similar because the loadings are so similar. 165 grain .40, 147 grain 9mm, 158 grain .38 +P, not much difference between those three...and, they will all get the job done as well as any standard handgun loading.