Actually it has been proven that residual velocity (starting from a higher one) and a reduced load do about the same damage.
Specifically mentioned here on actual animals and wet newsprint.
I'm sure it's interesting.....
I will string with Bill Steiger's work and that of others dating back decades when it comes to RPM's, velocity, and bullet expansion. They found a difference. I will defer to Steigers since he developed one of the best premium hunting bullets ever made.
Tin foil bullets may be a completely different story from premium, heavy jacket hunting bullets. I don't care what happens with the squishy stuff.